MV T3.06Posting Shapes: Circle, Square, Triangle
The child posts a cylinder, a cube, and a triangular prism, each first into a box with one matching hole and later into one box with three holes.
Safety
- Each solid must not fit the small parts test cylinder (1.25 in. wide × 2.25 in. deep); solids at least 3.5 cm (1.4 in.) in their smallest direction do not fit.
- Check the corners of the cube and prism for sharp edges or splinters, and the drawer for gaps that trap fingers.
Presentation
- 1
Start with the circle box. Carry it to the table and sit beside the child, with the cylinder on the tray.
- 2
Pick up the cylinder, turn it so its round end faces down, and hold it over the hole. Lower it in and let it drop. Open the drawer and take it out.
- 3
Offer the circle box for several days before the square box.
- 4
For the square box, hold the cube over the hole and turn it slowly until its edges line up with the edges of the hole, then let it drop. Lining up the edges is the point of interest.
- 5
Offer the triangle box the same way once the child posts the cube without help.
- 6
When the child posts all three solids into the single-hole boxes, show the three-hole box: pick up one solid, hold it over each hole in turn, and let it drop into the one it fits. Name it once: 'Square.'
- 7
Let the child try each solid. If a solid does not go in, wait; turning it and trying another hole is the work.
- 8
When the child stops, take the solids out of the drawer and return the box and tray to the shelf.
Extensions, easiest to hardest
- Rectangle and half-circle solids, each on its own single-hole box
- A box with four or five holes and one solid for each
- Matching flat shapes to their outlines (see Matching Shapes to Outlines in the Sensorial area)
Control of error
Each solid goes only into the hole with its shape, and only when turned so its edges line up with the hole.
Ready to move on when the child…
- Turns the cube and prism to line up with the hole before pushing
- Chooses the right hole on the three-hole box on the first or second try
- Posts all three solids without help
Guide note
Shape sorters sold for this age often have 6–12 holes at once. Montessori practice starts with one hole per box so the child meets one difficulty at a time; the box with several holes comes last.