Repeat x
If you want to run one or more commands a number of times, you can use the repeat command with x being the number of times you want to repeat.
The block of commands is enclosed with brackets [ and ]. Actually the [ bracket is optional but the closing ] bracket is needed so the repeat command knows when to go back to the start.
You can also "nest" repeat commands - that is you can have a repeat command within another repeat command.
Example:
REPEAT 5
[
FD 50
RT 45
]