There's so much more to Maths than what you learn in school. After teaching these students to count in binary, I labeled their fingers with 1, 2, 4, 8 and 16, so they could dance their fingers as they counted from 1 to 31. They used that information to assign each letter of the alphabet a binary number, then translated those to paper using two colours, one for the number 0, and one for the number 1.
As a challenge I threw out the idea that they didn't have to write their secret message as a rectangle; they could make it a spiral, a snake or something I had never thought of. What they came up with was just wonderful!
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