This is "grapes". It is graph making software we used this time.(This graph is y=1/2x^2)
First of all we made trout. We wrote numbers horizontally and alphabet vertically.
I placed an eraser in accordance with it.
By the way, we used the "grapes" to make trout.
Place four mirrors on the parabola and look for the focus with the eraser shown there.
The eraser was in the mirror, but the scale is too small to understand. " the mirror is big ..."
I tried to enlarge the parabola
We bought a small mirror, but unlike a big mirror, we could not stand ...
I devised and fixed it.