import cadquery as cq
w0=cq.Workplane('ZX',origin=(0,40,0))
w1=cq.Workplane('YZ',origin=(-2,0,0))
r=w0.workplane(offset=-81/2).moveTo(-34.5,68.5).box(21,63,81).union(w0.sketch().push([(32,-77)]).rect(22,46).rect(22,12,mode='s').finalize().extrude(-56)).union(w1.workplane(offset=56/2).moveTo(-3.5,40.5).box(3,9,56))