Can you explain the following sentences taken from kb page 747:
This design is not optimal because the user can't do anything while the machine
is busy and while there are other shapes to define. We need to improve the situation.
A simple solution is to separate the processes into two different threads, one of
them interacting with the user and another managing the hardware. The user thread
sends the instructions to the hardware thread and then goes back to interacting with
the user immediately. The hardware thread receives the instructions from the user
thread and starts directing the machine immediately. Both threads use a common
object to communicate, which holds the current design being processed.
Is the operator the user? The other thread is the machine/hardware. The idea here is that there is no third object (like in the bank account example) right? Two threads need each other and interact.