How to play

  1. Pick a world. Each world has 12 mystery shadows. They get harder as you go.
  2. Look at the shadow. What do you think it is?
  3. Drag blocks onto the build mat. Click a block to turn it.
  4. Make your build the exact same shape as the shadow. The shadow is shrunk, so your build will be bigger.
  5. When the shapes match, the shadow lights up and tells you its name.
  6. Want more stars? Build it again with fewer blocks.

Block facts

Every block is made of little triangles. Big blocks can do the job of many small ones.

Pick a world

My badges

Your stars are saved on this computer only.

Teacher note
  • How it is organized: 10 worlds with 12 shadows each, 120 in all. Inside each world the shadows are sorted from easiest to hardest, so later shadows are bigger and need more blocks. Nothing is locked, so you can send students to any world or shadow number.
  • What students practice: putting shapes together to make new shapes, turning shapes in their heads, and measuring area by counting triangles.
  • The math inside: 1 hexagon = 2 trapezoids = 3 rhombuses = 6 triangles. The "Shadow size" and "Your build" counters show area in triangles, so students can reason about how much is left to fill.
  • Stars: 1 star for any correct build, 2 stars for a build close to the best (within 3 to 5 blocks), 3 stars for the fewest blocks possible. The fewest number was worked out by computer for each shadow, so 3 stars is a real challenge.
  • Why two boxes: students cannot drop blocks on the shadow. They have to study it, then rebuild it on the mat, which takes more thinking than tracing.
  • Help button: "Show triangle lines" draws the triangle grid on the shadow so students can count. It does not show where the blocks go.
  • No supplies needed. If you have real pattern blocks, students can build the same shadows at their desks, since only the hexagon, trapezoid, blue rhombus, and triangle are used.
  • Team idea: one partner builds, the other is the "block counter" who looks for places to trade small blocks for a bigger one.