He suggests
The child sorts them by color and a form.
The teacher puts the yellow triangle on the middle of a carpet.
He suggests to apply three red triangles to this triangle.
So the hexagon turns out.
Then the teacher cleans a yellow triangle.
The child fills a vacant place other red triangles.
Then the teacher suggests the child to put with each other gray triangles.
The child compares two hexagons.
At last, the child puts with each other green triangles on black lines so that turned out a trapeze.
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