The idea

If the concept is about rotation, the tool should rotate. I wanted students to physically spin a 2D shape and watch a solid appear in real time, not as an animation, not as a diagram, but as something they could hold, turn, and feel resist in their hands.

The Making

The shapes were laser cut from acrylic sheet and mounted on 3D printed bases using LEGO axles from the Maker Space, the kind normally used for wheels. They were the right diameter, easy to spin, and already available. No overengineering. The base held the axis, the acrylic pieces fanned out around it, and when you spun them the solid emerged: a rectangle became a cylinder, a triangle became a cone, a semicircle became a sphere.

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The first version was in clear acrylic. It worked mechanically but visually the transparency made it harder to read the solid form. The second version used amber acrylic, the opacity made the rotation effect much more legible, and the resulting shape became immediately obvious.

In the classroom

Year 8 students used the models to explore the relationship between 2D profiles and 3D solids. The interaction was intentionally simple: pick it up, spin it, see it. No instructions needed.

What I learned

The LEGO axle wasn't a compromise, it was the right answer. It spun smoothly, it was the right scale, and it made the object feel familiar to the students. Sometimes the best component is the one already on the shelf.