In primary school, we often introduce the concept of classification using logic blocks, which are a set of blocks that have different attributes like:
- shape: triangle, circle, square, rectangle
- size: small or large
- thickness: thick or thin
- colour: yellow, blue, or red
which makes a set of 48 distinct blocks.
Some sets include an additional colour (green) or shape (regular hexagon or isosceles trapezoid), etc., in order to increase the possibilities for use when teaching.
We can construct sequences of blocks using a rule; such as, one block is added to another if it has exactly two distinct attributes as the preceding one.