12. The following infinite sequence composed of $1$ and $2$ has an interesting feature: starting from the first term, group the terms with the same number together, then write down the number of terms in each group in order, and the infinite sequence formed by these numbers is exactly the sequence itself. This sequence is called the Kolakoski sequence. According to this feature, continue to write the next 8 terms $\qquad$ (from the 14th term to the 21st term), if it is known that the sum of the first 50 terms of this sequence is 75, and the 50th term is 2, then we can know the 73rd term, 74th term, 75th term, and 76th term respectively $\qquad$
Parse:
Write two columns of numbers in two rows
The previous question can be filled out according to the pattern:
$122112122122112112212 \ldots .$.
1221121221221......

So the 14th to 21st terms are 12112212
If the first 50 terms are all 1, then the sum should be 50, but now the sum is 75, which means there are 25 2s. Each 2 means one more number in the upper row. Now there are 25, so the 50th number 2 corresponds to the 74th and 75th numbers in the upper row, so the 73rd, 74th, 75th, and 76th numbers form $a b b a$

Because each additional number in the lower row means the corresponding number in the upper row changes its parity once, for example, the second number in the lower row is 2, corresponding to the upper row number changing from 1 to 2, the second number 2 in the lower row, corresponding to the upper row number changing to $1, \cdots \cdots$ and so on, the 50th number in the lower row means the corresponding number has changed its parity 49 times, so the parity is different from the first, the first is 1, so the 74th and 75th numbers are 2, so the numbers from 73 to 76 are 1221.