Whoops! Was that part of the drawing supposed to be blue instead of red? No worries—each of these adorable turtle-shaped crayons has an eraser for a shell. Just rub out the wrong color and draw in the right one. (The original mark doesn't erase away completely, but becomes faint enough that you can draw over it with a new color.) The four basic colors—red, yellow, blue, and green—are also ideal for learning blended techniques; color with red and blue together to make purple, or red and green to make brown. (Not recommended for children under 3.)