0.2 Parabola tool

Parabola; X to the power of 2

Detailed description
The inner space of this U-shaped tool has the contour of the formula X to the power of two.
The two poles of the U have indented centimetre indications along the outside.
Three medium size alignment indents are provided near the bottom; one in the middle and one in each of the two poles.
Pushpin markers are provided in the top surface of the tool.
The contour of the graph goes down and up again. At the two ends of the contour pen blockers are provided.
Indented positions along the curve reflect Y values for X equals -2, -1, -0,5, 0, 0,5, 1 and 2.