Geometric Shape Visualization Puzzle

thingiverse

I created this object as a possible answer key for a teacher who assigns the following visualization task to their students: Can you imagine a three-dimensional solid that can completely fill and pass through three different holes - a square, a triangle, and a circle? The same shape must be used to fit through all three and cannot have any moving parts. The diameter of the circle and square and the base and height of the triangle are all equal in length (for example, circle diameter = 1.0 units, square diameter = 1.0 units, triangle base = 1.0 unit, triangle height = 1.0 unit).