The rope will be then following 2 way relay.
The main volume would be on the base ground, floor level.
And the carrier (machine) climbing up the stairs
and relaying the rope with assist of a powerful motor,
will take from the main volume with rotation and drop
the cube positioned in the interlocked shape.
If curious about the interlocked shape, refer to my
other designs on the sea pillars, the valve design.
Simply a hollowed out space with protruding edges
that enwraps around the interlocking shape.
So basically a hollowed out rectangle with space
for something to go in.
Trying to help you complete if you weren't thinking of this Mr Musk...