Leon generally paints contemporary themes which involves environmental concerns and raises questions about the livability in this world.
Numerous exhibitions organized by Beeldkracht Gallery gave him recognition in the international art scene. As the art director of Planet Streetpainting Keer designs and creates 2-D and 3-D street art in the Netherlands and abroad. The 3-D Lego terracotta army is one of those creations. It was painted at the 2011 international Sarasota Chalk Festival.
- . surreal art collective
- Leon Keer
- , nrc: nederlanders tekenen 3D terracotta Lego-leger op straat.
- , curated (daily news).
-  International Sarasota Chalk Festival in Florida.
- , huffingtonpost: Leon Keer, Chalk Artist, Creates 'Piggy Bank' Optical Illusion In Japan.
- , lost at e minor: 4D Street Art.
- Lego Man artist revealed
- Ego Leonard
Leon Keer's official webpages