You can drag any square into any of the first 6 lists.
Horizontal list 1 (grows right):
Vertical list 1:
Vertical list 2 (style changes on drag hover):
Horizontal list 3 (grows left):
Bug: drop position is off by one.
Horizontal list 5 (grows right, has multiple rows, hysteresis is enabled):
Bug: can't drop into the last row.
The items in this list can be moved around with shift-dragging: