Make a square from A4 paper

Lay the short edge of an A4 sheet along the long edge, fold, and cut off the strip that sticks out. All you need is a pair of scissors.

Steps

Step 1Place the A4 sheet upright. Fold the top edge down to meet the right edge, making a triangle.
Step 2Cut off the rectangle that sticks out below the triangle, along the triangle's edge.
Step 3Unfold the triangle. You now have a square.
Finished