Move with Arrows keys. Anything more than 4 blocks away is not drawn.
Modified the project to remove incorrectly drawn center square which is hidden by a darkness mask in original project. Attempting to add depth cueing by brightness. Purpose is to have a 100% pen drawing engine that can be ported to Vectrex display. To do: use perspective spacing for walls as in https://scratch.mit.edu/projects/157841571/. (Currently spacing is linear)
