Select and move blocks

[newsch]

I made a thread diagram with #2, and the main thing that got in my way was having to move sections around.

PARENT
  |
"Creating child 0" ------------------ CHILD 0
  |                                      |
 fork                                 sleep 0
  |                                      |
"Creating child 1" ---- CHILD 1  "Hello from child 0"
  |                       |              |
 fork                  sleep 1    /---< exit
  |                       |      /
"Hello from parent" /-----|-----/
  |           /----/      |
wait 0 <-----/    "Hello from child 1"
  |                       |
wait 1 <---------------< exit
  |
exit