diff --git a/papers/format.md b/papers/format.md
index 39e5e04e5..09ea9f74b 100644
--- a/papers/format.md
+++ b/papers/format.md
@@ -643,7 +643,8 @@ size | description
  ??? | pattern data
      | - read a byte per row.
      | - if it is 0xff, end of data. the rest of the pattern is empty.
-     | - if bit 7 is set, then read bit 0-6 as "skip N+2 rows".
+     | - if bit 7 is set, then skip N+2 rows. N is bits 0-6.
+     |   - for example, $80 means skip 2 rows, $81 means skip 3, $82 means 4 and so on.
      | - if bit 7 is clear, then:
      |   - bit 0: note present
      |   - bit 1: ins present
@@ -652,6 +653,7 @@ size | description
      |   - bit 4: effect value 0 present
      |   - bit 5: other effects (0-3) present
      |   - bit 6: other effects (4-7) present
+     |   - if none of these bits are set, then skip 1 row.
      | - if bit 5 is set, read another byte:
      |   - bit 0: effect 0 present
      |   - bit 1: effect value 0 present