Snap to grid (button and/or keystroke) would be great

[danbri]

(Revisiting this, great to see the determinant/eigenvector improvements :)

It would be nice to have a quick way to snap the cross-hair position to the nearest whole number (or maybe in 0.5-sized steps?).

Also thinking about determinant, perhaps you could display the numeric value somewhere, and flip the colour of the shaded area when it is negative?

[shadanan]

Good ideas. I did the snapping and the inverted determinant color. I want to think of a nicer way to display the results – right now, I'm drawing them, but I think there might be a prettier / less cluttered way of doing it. I'll save that for later. Thanks for the tips!