Hello Idon'tknow !
Well i see some figures in the mist that are great ! So straight to the point : Yes, for me you should do an half hour of this exercice on top of doing class if you want to improve faster. If you don't, then just chill, attempt to your classes when you want and that's pretty it :)
This is an actual exercice, without you noticing it, your brain is bulking up to understand what you see and trying to draw in 30s. It is actually kinda stressful for your brain, and that's all the point. To learn, you must face repetition, to learn better : facing repetition in a difficult and abnormal condition. I see that exercise that way. I'd be so much better at a coffee, drawing people passing by without caring much. But i'd be in a much more cooler mentality, so i would probably learn a lot slower and in a more sloppy way.
Trying things with a timer who's going crazy but staying focus and intellectualize it to do each line voluntarily and consciously is probably the safest and strongest way to progress. But it can't be all in a stand alone, that's why if you want to progress faster you should keep going with that exercise on top of your classes everyday more than 20min.
Stay in shape body and mind and so your pen, but the better way to do it in long terms is to taking fun at it so enjoy ! :)
Hope you the best, ++
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