Inspired by Alexandre Villares and his sketch-a-day, I have been coding sketches everyday and publishing the code here and at the github.com/ericof/sketch-a-day repository.
Triangles and nothing else
Subdivision
Impossible day
TAU, TAU, TAU, TAU
Public transport seating
One million lines
Landscape with spheres
Landscape w/ primitive shapes
Isometric art - Proto City
Black on Black
The Answer (in 42 lines of code, including comments)
Layers upon layers upon layers