I recommend using resolution 3 because it does not struggle so much with running fast enough. Arrow keys to move the dot about, it updates the shading every fraction of a second or so. Use turbo mode.
If you want resolution 1 use this: https://turbowarp.org/556245237 This is just a pen operated shading test. Resolution 1 is VERY slow and VERY laggy. Resolution 2 is slow and kinda laggy. ***Change log*** v1.6 added frame rate tracker (3-9 fps!) v1.5 - changed from stamping to pen now looks far better and makes resolution 2 is more stable v1.4 - Variables now only appear when the cursor is at the top v1.3 - Added size and speed v1.2 - 3 resolutions now! v1.0 - Initial release