掲示板 Forums - Overlay in garden

Short answer: you cannot. Long answer: do you see those red lines behind your items while you're editing your garden? If the red area from one item touches the red area of another one, a popup "overlap" will appear, telling you that you need to move at least one of them. This is probably to prevent people from stacking everything on top of each other, or something similar. You can make items look like overlapping though, when you place them really close behind or in front. Usually the red area isn't behind the whole object, just on the part where it 'touches the ground'. For example, I did this in my own garden to make it look like the bridge is over the pond.