I was fortunate enough to have a PPL(H) instructor who would answer my such questions by placing our R22 near to such an obstacle (tree in remote corner of secret airfield nr Stratford on Avon) and request me to observe. Light winds, good viz.
One notices that the blades are not blades anymore but a tangible disc.
Compare with rapidly whirling a string with a rock attached to the end over your head whilst next to a wall - you can move in very close, and 'tick' the wall (See Chicken Hawk) as long as you can watch the disc.
Of course all this takes place with your feet on the ground, good viz, both feet doing nothing and one hand in pocket.
Real pilots manage to do similar with radio load, multi-crew demands, wind, rain, turbulence, dark, instrument scans and someone on the end of a winch cable 50 feet above jagged rocks and thundering sea state.
The only consolation most of us have is they don't use an R22 to do it.
Regards
Cron