GrblGru, developer of the 3D-simulation for CNC-machines of the same name, has donated this nice wooden puzzle. The complexity shows actually show when you try to put the pieces together.
download at Thingiverse buy me a coffee commercial license?
MaterialPlywood AudienceAdultsAudienceKids ComplexitySimple PurposeLeisure
The drawing needs to be scaled to match the material width.