NEW BASIC SHAPES: CURVES and HOLLOW CIRCLES. There are so many custom-built items that require curves and premade smooth curve and hollow circles basic shapes would add a lot of smoothness to those detailed builds! The basic curve could be resized to, for example, make custom 3d roof shingles. The hollow circles could be useful to make tubes and circular borders on things like signs. Theme Park Tycoon 2 has really nice basic curves, (see image for reference)