7:19 PM, Sunday April 28th 2024
Equilateral refers to keeping the scale of the form you're constructing relatively similar in each dimension. That is not the same as simply keeping the length of your Y's edges equal on the page, because this doesn't account for distances extending into the depth of the scene.
That said, it is not something you need to worry about being entirely precise - it's just asking you not to intentionally play with forms that are extremely long in any one dimension.