import cadquery as cq
w0=cq.Workplane('XY',origin=(0,0,7))
w1=cq.Workplane('YZ',origin=(4,0,0))
r=w0.workplane(offset=4/2).moveTo(0,21).box(36,58,4).union(w1.workplane(offset=-17/2).moveTo(-20,0).cylinder(17,30))