In normal programming code, each code block must be executed completely before the next block is run. This means, for example, that you can only have one robot moving at a time. Sometimes, however, you want multiple robots to move together.

It's possible to do this using a special type of block called Non-Blocking (NB) blocks. With a "non-blocking" block, RoboBlockly will start the block's execution and then immediately move on to the next blocks in sequence while the non-blocking block continues executing. That is, the "non-blocking" block does not block execution of later blocks (thus the name "non-blocking"). 

An example of a non-blocking block is the driveDistanceNB block:

We also use the moveWait block with non-blocking blocks to wait for all the non-blocking action to finish before ending the program:

Watch the video to learn more about how to use non-blocking blocks.