Smooth wall sprites.

Updates

Added back the algorithm to choose the correct sprites for adjacent walls. Created some new walls just to match the flat look of everything else.

Swapped the time travel controls to make these primary, while undo/redo are secondary.

Toroban - Smooth walls

Future

All sprites will be reworked to be 2.5D, with a consistent perspective. The walls are important to get right, since the color walls will need to move up/down for clearly visualizing that mechanic.

The theme and color palette need to be decided on and adhered to. This should improve the overall look and design.