2 documents, A and B
Step 1: A: create black screen, create a series of overlapping shape
Step 2: A: Use Magic wand select any portion of overlapped shape U want
Setp 3: A: Still in magic wand tool, click and drag selection, drop selection anywhere on B
Setp 4: B: Press crt-c / command -c to copy section on B
Step 5: Go back to A, crt-v/ command -v to paste
simplfied: use marquee tool make selection on black Doc (A) (retangle ants rite)
make sure tool inside selection (arrow with small rect)
drag selection to B(any where)
copy
go back doc A (selection still on rite?) Paste
essentially using selection on A to copy exact same selection from B paste back to A