The final rule in solving Shapedoku puzzles is an extremely important one: The name that is listed is the most specific name that can be used to describe that shape. For example, a square shape would be listed as a square and not as a rhombus, parallelogram, rectangle, or quadrilateral. And a shape that is listed as an isosceles triangle must have exactly two sides of the same length and cannot contain a right angle (it would then be called an isosceles right triangle).