Common Mistakes (and How to Avoid Them)

• Counting “by levels” without checking for large cross triangles: The typical culprit is a forgotten 3-level triangle.
• We omit the inverted (“downward”) triangles: they are less visible, but still present (7 in total).
• Add imaginary vertical lines: Some puzzle variations include real vertical lines, which change the total (but never to 26). Make sure you’ve set the position correctly before finishing.
• Double some triangles: follow a logical progression based on size to avoid duplicates.

Want to learn more?

• Change the number of rows: Try the formula with   n   = 3 or   n   = 5 and compare it to a manual count – perfect for training the eye.
• Time yourself: Give yourself 60 seconds to reach 27. The secret? Count the “up” part first, then add the “down” part.
• Tell a friend: teach a trick and you’ll remember it forever (and win your next puzzle battle).

Because behind a simple triangle often hides a little lesson in logic… and the discreet pleasure of having the last word!