So this is one strand, this is the five end of the strand and this is the three end of the strand and it runs along our common axis in the following direction from the top to the bottom. The second polynucleotide chain is this chain here and it runs in the opposite direction. So it essentially winds around the comet axis and it runs from the bottom to the top. So we have the five end here and the three end here for the first chain and the three end here and the five end here for that second chain. And so in this particular case, let's imagine that the axis of rotation basically lies along our Y axis and these two strands essentially curl around, they coil around our common axis. This is point number one.