This big Blendy Pens kit contains 10 hidden-pattern coloring sheets . . . and dozens of color possibilities! The 12 color-rich markers for kids combine to make 66 two-color or hundreds of three-color blends: Simply snap two Blendy Pens into a Fusion Chamber, twist and see the colors mix. Mix a little or a lot--you control the intensity! Use your custom color blends to color in the Surprise Art coloring sheets and reveal the hidden patterns, or use them to give your doodles amazing effects on regular paper. Makes a great travel toy.