text: You will view a stream of letters on the screen, one letter at a time.
  At the beginning of a block, you are told a number N.
  You have to remember the last N letters you saw since the beginning of the block.
  If the letter you see matches the letter N trials ago, press F, otherwise press I.
  The case of the letter is irrelevant, so "t" matches "T" for example.
  If you make more than 5 mistakes in a block, N is decreased by 1.
  If you make fewer than 3 mistakes in a block, N is increased by 1.
  You will go through 20 blocks with 20+N trials each.
      
  Block 0, N = 2:
  You see the letter G.
  You see the letter T.
  You see the letter V.
  You see the letter g.
  You see the letter G and press <<F>>.
  You see the letter g and press <<F>>.
  You see the letter B.
  You see the letter G and press <<F>>.
  You see the letter d.
  You see the letter D.
  You see the letter D and press <<F>>.
  You see the letter t.
  You see the letter t.
  You see the letter t and press <<F>>.
  You see the letter T.
  You see the letter G and press <<F>>.
  You see the letter t.
  You see the letter T.
  You see the letter V.
  You see the letter t and press <<F>>.
  You see the letter D.
  You see the letter g.
  
  Block 1, N = 1:
  You see the letter d.
  You see the letter D.
  You see the letter b.
  You see the letter B and press <<F>>.
  You see the letter D.
  You see the letter d and press <<F>>.
  You see the letter T.
  You see the letter t and press <<F>>.
  You see the letter D.
  You see the letter D and press <<F>>.
  You see the letter v.
  You see the letter t.
  You see the letter D.
  You see the letter t and press <<F>>.
  You see the letter T and press <<F>>.
  You see the letter T and press <<F>>.
  You see the letter V.
  You see the letter g.
  You see the letter B and press <<F>>.
  You see the letter G.
  You see the letter T.
  
  Block 2, N = 1:
  You see the letter G.
  You see the letter g and press <<F>>.
  You see the letter b.
  You see the letter g.
  You see the letter V.
  You see the letter G.
  You see the letter G and press <<F>>.
  You see the letter g and press <<F>>.
  You see the letter V.
  You see the letter v and press <<F>>.
  You see the letter T.
  You see the letter G.
  You see the letter b.
  You see the letter D.
  You see the letter b.
  You see the letter D.
  You see the letter d and press <<F>>.
  You see the letter v.
  You see the letter v and press <<F>>.
  You see the letter T.
  You see the letter t.
  
  Block 3, N = 1:
  You see the letter g.
  You see the letter v.
  You see the letter V.
  You see the letter B.
  You see the letter b and press <<F>>.
  You see the letter T.
  You see the letter g.
  You see the letter t.
  You see the letter t and press <<F>>.
  You see the letter D.
  You see the letter G.
  You see the letter V.
  You see the letter D.
  You see the letter d.
  You see the letter D.
  You see the letter v.
  You see the letter V and press <<F>>.
  You see the letter G.
  You see the letter G and press <<F>>.
  You see the letter T.
  You see the letter g.
  
  Block 4, N = 1:
  You see the letter d.
  You see the letter g and press <<I>>.
  You see the letter G and press <<F>>.
  You see the letter D and press <<I>>.
  You see the letter d and press <<I>>.
  You see the letter G and press <<I>>.
  You see the letter G and press <<F>>.
  You see the letter t and press <<I>>.
  You see the letter T and press <<I>>.
  You see the letter T and press <<F>>.
  You see the letter v and press <<I>>.
  You see the letter G and press <<I>>.
  You see the letter G and press <<F>>.
  You see the letter d and press <<I>>.
  You see the letter v and press <<I>>.
  You see the letter d and press <<F>>.
  You see the letter T and press <<I>>.
  You see the letter g and press <<I>>.
  You see the letter v and press <<I>>.
  You see the letter V and press <<F>>.
  You see the letter T and press <<I>>.
  
  Block 5, N = 1:
  You see the letter B.
  You see the letter V and press <<I>>.
  You see the letter T and press <<I>>.
  You see the letter d and press <<I>>.
  You see the letter T and press <<I>>.
  You see the letter T and press <<I>>.
  You see the letter B and press <<I>>.
  You see the letter b and press <<F>>.
  You see the letter v and press <<I>>.
  You see the letter v and press <<F>>.
  You see the letter d and press <<I>>.
  You see the letter D and press <<I>>.
  You see the letter G and press <<I>>.
  You see the letter v and press <<I>>.
  You see the letter V and press <<F>>.
  You see the letter t and press <<I>>.
  You see the letter d and press <<I>>.
  You see the letter T and press <<I>>.
  You see the letter t and press <<F>>.
  You see the letter t and press <<F>>.
  You see the letter D and press <<I>>.
  
  Block 6, N = 2:
  You see the letter v.
  You see the letter b.
  You see the letter b and press <<I>>.
  You see the letter G and press <<I>>.
  You see the letter g and press <<F>>.
  You see the letter G and press <<I>>.
  You see the letter b and press <<F>>.
  You see the letter G and press <<F>>.
  You see the letter T and press <<I>>.
  You see the letter D and press <<I>>.
  You see the letter B and press <<I>>.
  You see the letter b and press <<I>>.
  You see the letter T and press <<F>>.
  You see the letter t and press <<I>>.
  You see the letter t and press <<F>>.
  You see the letter b and press <<I>>.
  You see the letter t and press <<I>>.
  You see the letter V and press <<I>>.
  You see the letter V and press <<I>>.
  You see the letter V and press <<F>>.
  You see the letter v and press <<F>>.
  You see the letter V and press <<F>>.
  
  Block 7, N = 2:
  You see the letter D.
  You see the letter v.
  You see the letter b and press <<I>>.
  You see the letter d and press <<I>>.
  You see the letter d and press <<F>>.
  You see the letter d and press <<F>>.
  You see the letter t and press <<I>>.
  You see the letter b and press <<I>>.
  You see the letter V and press <<I>>.
  You see the letter G and press <<I>>.
  You see the letter v and press <<F>>.
  You see the letter B and press <<I>>.
  You see the letter D and press <<I>>.
  You see the letter b and press <<F>>.
  You see the letter D and press <<I>>.
  You see the letter b and press <<I>>.
  You see the letter D and press <<F>>.
  You see the letter b and press <<F>>.
  You see the letter g and press <<I>>.
  You see the letter G and press <<I>>.
  You see the letter t and press <<F>>.
  You see the letter T and press <<I>>.
  
  Block 8, N = 2:
  You see the letter v and press <<I>>.
  You see the letter g.
  You see the letter g and press <<F>>.
  You see the letter B and press <<I>>.
  You see the letter V and press <<I>>.
  You see the letter V and press <<F>>.
  You see the letter d and press <<I>>.
  You see the letter v and press <<F>>.
  You see the letter D and press <<I>>.
  You see the letter V and press <<F>>.
  You see the letter V and press <<I>>.
  You see the letter T and press <<I>>.
  You see the letter G and press <<I>>.
  You see the letter T and press <<F>>.
  You see the letter t and press <<I>>.
  You see the letter T and press <<F>>.
  You see the letter B and press <<I>>.
  You see the letter T and press <<I>>.
  You see the letter t and press <<F>>.
  You see the letter T and press <<I>>.
  You see the letter v and press <<I>>.
  You see the letter b and press <<I>>.
  
  Block 9, N = 1:
  You see the letter V.
  You see the letter B and press <<I>>.
  You see the letter D and press <<I>>.
  You see the letter t and press <<I>>.
  You see the letter g and press <<I>>.
  You see the letter t and press <<I>>.
  You see the letter t and press <<F>>.
  You see the letter T and press <<F>>.
  You see the letter g and press <<I>>.
  You see the letter B and press <<I>>.
  You see the letter T and press <<I>>.
  You see the letter T and press <<I>>.
  You see the letter T and press <<F>>.
  You see the letter G and press <<I>>.
  You see the letter g and press <<F>>.
  You see the letter G and press <<F>>.
  You see the letter B and press <<I>>.
  You see the letter G and press <<I>>.
  You see the letter G and press <<F>>.
  You see the letter D and press <<I>>.
  You see the letter v and press <<I>>.
  
  Block 10, N = 2:
  You see the letter d and press <<I>>.
  You see the letter G and press <<I>>.
  You see the letter B and press <<I>>.
  You see the letter g and press <<F>>.
  You see the letter d and press <<I>>.
  You see the letter g and press <<F>>.
  You see the letter d and press <<I>>.
  You see the letter t and press <<I>>.
  You see the letter b and press <<F>>.
  You see the letter V and press <<I>>.
  You see the letter B and press <<I>>.
  You see the letter v and press <<F>>.
  You see the letter b and press <<F>>.
  You see the letter v and press <<F>>.
  You see the letter v and press <<I>>.
  You see the letter D and press <<I>>.
  You see the letter g and press <<I>>.
  You see the letter g and press <<I>>.
  You see the letter V and press <<I>>.
  You see the letter V and press <<I>>.
  You see the letter b and press <<I>>.
  You see the letter g and press <<F>>.
  
  Block 11, N = 2:
  You see the letter g.
  You see the letter d and press <<I>>.
  You see the letter T and press <<I>>.
  You see the letter g and press <<F>>.
  You see the letter V and press <<I>>.
  You see the letter D and press <<I>>.
  You see the letter g and press <<I>>.
  You see the letter g and press <<F>>.
  You see the letter g and press <<F>>.
  You see the letter T and press <<I>>.
  You see the letter D and press <<I>>.
  You see the letter T and press <<F>>.
  You see the letter g and press <<I>>.
  You see the letter T and press <<F>>.
  You see the letter T and press <<I>>.
  You see the letter T and press <<F>>.
  You see the letter D and press <<I>>.
  You see the letter t and press <<F>>.
  You see the letter d and press <<F>>.
  You see the letter T and press <<F>>.
  You see the letter g and press <<I>>.
  You see the letter d and press <<I>>.
  
  Block 12, N = 3:
  You see the letter G.
  You see the letter t.
  You see the letter V.
  You see the letter G and press <<F>>.
  You see the letter t and press <<F>>.
  You see the letter D and press <<I>>.
  You see the letter v and press <<F>>.
  You see the letter T and press <<I>>.
  You see the letter d and press <<I>>.
  You see the letter t and press <<F>>.
  You see the letter v and press <<I>>.
  You see the letter d and press <<I>>.
  You see the letter T and press <<I>>.
  You see the letter T and press <<F>>.
  You see the letter b and press <<I>>.
  You see the letter g and press <<I>>.
  You see the letter v and press <<I>>.
  You see the letter d and press <<F>>.
  You see the letter V and press <<I>>.
  You see the letter D and press <<I>>.
  You see the letter v and press <<F>>.
  You see the letter v and press <<I>>.
  You see the letter G and press <<I>>.
  
  Block 13, N = 2:
  You see the letter b and press <<I>>.
  You see the letter d.
  You see the letter b and press <<F>>.
  You see the letter t and press <<I>>.
  You see the letter g and press <<I>>.
  You see the letter g and press <<I>>.
  You see the letter g and press <<F>>.
  You see the letter B and press <<I>>.
  You see the letter v and press <<I>>.
  You see the letter v and press <<F>>.
  You see the letter d and press <<I>>.
  You see the letter B and press <<I>>.
  You see the letter d and press <<I>>.
  You see the letter V and press <<I>>.
  You see the letter D and press <<F>>.
  You see the letter V and press <<F>>.
  You see the letter t and press <<I>>.
  You see the letter g and press <<I>>.
  You see the letter g and press <<I>>.
  You see the letter t and press <<I>>.
  You see the letter g and press <<I>>.
  You see the letter T and press <<F>>.
  
  Block 14, N = 2:
  You see the letter G.
  You see the letter V and press <<I>>.
  You see the letter V and press <<I>>.
  You see the letter V and press <<F>>.
  You see the letter V and press <<F>>.
  You see the letter v and press <<F>>.
  You see the letter G and press <<I>>.
  You see the letter t and press <<I>>.
  You see the letter t and press <<I>>.
  You see the letter t and press <<F>>.
  You see the letter t and press <<F>>.
  You see the letter d and press <<I>>.
  You see the letter D and press <<I>>.
  You see the letter b and press <<I>>.
  You see the letter D and press <<F>>.
  You see the letter V and press <<I>>.
  You see the letter b and press <<I>>.
  You see the letter V and press <<I>>.
  You see the letter D and press <<I>>.
  You see the letter T and press <<I>>.
  You see the letter v and press <<F>>.
  You see the letter v and press <<I>>.
  
  Block 15, N = 3:
  You see the letter v.
  You see the letter V and press <<I>>.
  You see the letter g and press <<I>>.
  You see the letter D and press <<I>>.
  You see the letter v and press <<F>>.
  You see the letter v and press <<I>>.
  You see the letter t and press <<I>>.
  You see the letter v and press <<F>>.
  You see the letter G and press <<I>>.
  You see the letter T and press <<I>>.
  You see the letter v and press <<F>>.
  You see the letter d.
  You see the letter D and press <<I>>.
  You see the letter T and press <<I>>.
  You see the letter v and press <<F>>.
  You see the letter B and press <<I>>.
  You see the letter T and press <<I>>.
  You see the letter B and press <<I>>.
  You see the letter T and press <<I>>.
  You see the letter d and press <<I>>.
  You see the letter b and press <<I>>.
  You see the letter t and press <<I>>.
  You see the letter V and press <<I>>.
  
  Block 16, N = 2:
  You see the letter b.
  You see the letter b and press <<I>>.
  You see the letter D and press <<I>>.
  You see the letter b and press <<F>>.
  You see the letter D and press <<F>>.
  You see the letter v and press <<I>>.
  You see the letter t and press <<I>>.
  You see the letter V and press <<F>>.
  You see the letter t and press <<I>>.
  You see the letter g and press <<I>>.
  You see the letter V and press <<I>>.
  You see the letter g and press <<I>>.
  You see the letter D and press <<F>>.
  You see the letter v and press <<I>>.
  You see the letter d and press <<I>>.
  You see the letter V and press <<F>>.
  You see the letter b and press <<I>>.
  You see the letter t.
  You see the letter G and press <<I>>.
  You see the letter B and press <<I>>.
  You see the letter d and press <<F>>.
  You see the letter g and press <<I>>.
  
  Block 17, N = 1:
  You see the letter D and press <<I>>.
  You see the letter d and press <<I>>.
  You see the letter G.
  You see the letter g and press <<F>>.
  You see the letter g and press <<F>>.
  You see the letter D and press <<I>>.
  You see the letter D and press <<I>>.
  You see the letter b and press <<I>>.
  You see the letter T and press <<I>>.
  You see the letter v and press <<I>>.
  You see the letter g and press <<I>>.
  You see the letter v and press <<I>>.
  You see the letter t and press <<I>>.
  You see the letter v and press <<I>>.
  You see the letter V and press <<F>>.
  You see the letter T and press <<I>>.
  You see the letter t and press <<F>>.
  You see the letter D and press <<I>>.
  You see the letter v and press <<I>>.
  You see the letter V and press <<F>>.
  You see the letter b and press <<I>>.
  
  Block 18, N = 1:
  You see the letter t and press <<I>>.
  You see the letter T and press <<I>>.
  You see the letter t and press <<F>>.
  You see the letter b and press <<I>>.
  You see the letter b and press <<F>>.
  You see the letter v and press <<I>>.
  You see the letter d and press <<I>>.
  You see the letter T and press <<I>>.
  You see the letter V and press <<I>>.
  You see the letter v and press <<F>>.
  You see the letter g and press <<I>>.
  You see the letter d and press <<I>>.
  You see the letter g and press <<I>>.
  You see the letter D and press <<I>>.
  You see the letter v and press <<I>>.
  You see the letter g and press <<I>>.
  You see the letter g and press <<F>>.
  You see the letter g and press <<F>>.
  You see the letter v and press <<I>>.
  You see the letter D and press <<I>>.
  You see the letter D and press <<F>>.
  
  Block 19, N = 2:
  You see the letter V.
  You see the letter D and press <<I>>.
  You see the letter V and press <<I>>.
  You see the letter V and press <<F>>.
  You see the letter V and press <<I>>.
  You see the letter v and press <<I>>.
  You see the letter b and press <<I>>.
  You see the letter v and press <<F>>.
  You see the letter G and press <<I>>.
  You see the letter T and press <<I>>.
  You see the letter g and press <<F>>.
  You see the letter D and press <<I>>.
  You see the letter B and press <<I>>.
  You see the letter t and press <<F>>.
  You see the letter T and press <<I>>.
  You see the letter T and press <<F>>.
  You see the letter t and press <<F>>.
  You see the letter g and press <<I>>.
  You see the letter V and press <<I>>.
  You see the letter v and press <<I>>.
  You see the letter B and press <<I>>.
  You see the letter t and press <<I>>.
  