xy _ z _ xxyx _ px _ yxzpx _ yxzpx

In a blanked letter series that repeats a fixed block several times, each copy of the block usually has its blank(s) in different positions from the others; comparing the several copies position-by-position recovers the complete block, and each blank is then simply the letter that occupies its position in the block.

1. Split the 24 letters (including blanks) into four groups of six, matching the block's four repeats: positions 1-6, 7-12, 13-18, 19-24.

2. Compare the four groups position-by-position. Local position 1 reads x wherever it isn't blank (groups 1 and 2); local position 2 reads y in every group; local position 3 reads x wherever it isn't blank (groups 2, 3, 4); local position 4 reads z wherever it isn't blank (groups 1, 3, 4); local position 5 reads p wherever it isn't blank (groups 2, 3, 4); local position 6 reads x in every group. So the repeating block is x, y, x, z, p, x, that is xyxzpx.

3. Reading each blank off this fixed block: the two blanks in the first group sit at local positions 3 and 5, giving x and p; the blank in the second group sits at local position 4, giving z; the blanks in the third and fourth groups both sit at local position 1, each giving x.

Substituting x, p, z, x, x back into their five slots reconstructs xyxzpx four times in a row with nothing left over, confirming the block-based reading is consistent throughout the sequence.

The five blanks, read in the order they appear, are x, p, z, x, x, that is xpzxx.