A short web document by Ralph Griswold explaining how to fix integer-sequence-derived t-sequences (threading and treadling sequences) that have missing values and would need more shafts or treadles than are used. It compares compression (closing gaps) with normalization (renumbering values in order of first appearance), using n² mod 30 as the example. Drafts and drawdowns show that both methods give the same result with a direct tie-up but differ with a 2/2 twill tie-up. It concludes that normalization generally looks more coherent and is useful for comparing sequences.