Lift Bottom

You may want to shoot the photographer with this one!
The brown 3hx3hx1h flanged plate in the pic slides up and down on two 4mm carbon fibre rods and carries with it an arrangement of couplings and rods that are used to push up a pair of marbles at the base of the lift. When the two columns of marbles reach their highest point, the pointed ends of a pair of counterweighted pawls slip under them and hold them in place while the plate descends. When the bottom of the travel is reached, the next pair of marbles roll into place on their guide rails. All this, of course, enables a pair of marbles at the tops of the columns to roll out on to their guide rails and so on to their feed arms.