https://www.youtube.com/watch?v=wwIysnVmAUg
Then go interview with them. They don't stand next and engage you while you're working at the white board. Instead, they sit at the opposite end of the table and type out your code line by line on their laptops so at the end they can see if whatever you scribbled actually compiles.
The laptop requirement just encourages disengagement. I knew the problem and how to get to the optimal solution for my first round at Google so it didn't affect my performance, but I was pretty disappointed because my interviewer, between typing up the lines I wrote on the board, was completely occupied answering email and Slack messages and barely said anything or made eye contact aside from the occasional "mhm" or nod. Had I gotten stuck at any point I don't think I would have been able to get any help, certainly not any help like I would get from a coworker in a truly collaborative scenario.