Find a counter example to following bad definition: a square has four right angles

a flat figure with 4 equal straight sides and four right angles

Answer: Hello there!

We want to find a counterexample to: "a square has four right angles" then we need to find a figure that has four right angles and is not a square.

A first example can be a cross (two segments that cut each other and are perpendicular), but let's think in a geometric shape.

Think on a square that in the middle of each side has a small semicircle; this shape still has four right angles but is not more a square.

There you have two counterexamples of the definition given.