concrete interlocking block 3d model

Create a 3D model of a universal interlocking concrete hollow block. Size: 400×200×150 mm, rectangular with slight 2–3 mm edge fillet. Include 2 vertical hollow cores and a central 50 mm rebar hole. Top: raised cross (+) male connector, 15 mm height, slight taper. Bottom: matching recessed cross slot, 15 mm depth. Left: full-length dovetail groove (female, 5–7° angle). Right: matching dovetail ridge (male). Front: symmetrical wave/puzzle interlock. Back: inverse wave pattern. Design must be fully symmetrical and connect in vertical and horizontal orientations. Concrete texture, light gray, realistic. Show 1 block and 2 connected blocks (stacked and side-connected). Clean studio background, high detail, precise geometry.