import cadquery as cq

# パラメトリックなブラケットの例
width = 30
height = 20
thickness = 3
hole_dia = 4

result = (
    cq.Workplane("XY")
    .box(width, height, thickness)
    .faces(">Z")
    .workplane()
    .rect(width - 10, height - 10, forConstruction=True)
    .vertices()
    .hole(hole_dia)
    .edges("|Z")
    .fillet(2)
)

show_object(result)  # CQ-editor 内で実行