For the number and writing cubes, I cannot definitively prove that there is no additional meaning behind them, but there does not seem to be any evidence implying otherwise. Taken at face value, they're clearly tools for Fez denizens to stamp out numbers and letters. This is implied by:
Writing prompt cubes for back to school! Each cube has 6 different writing prompts. Toss to students, or have them toss to each other to find a fun writing prompt. Great for conversation starters as a whole class as well!
Spark brainstorming and imagination with these Writing Prompt Cubes students can use in both creative storytelling and nonfiction writing activities. With different writing prompts on every side (36 prompts total), foam cubes offer a variety of ideas for individual or group writing projects. Cubes are quiet when rolled?perfect for centers. Activity Guide included. Cubes measure 1 5/8?.