This level editor was written for python 3. If you don't have python 3 then install it from python.org. Once installed drag lawnscaper.py to python.exe. You will be prompted to load the lawn_mower.nes rom and then use the below controls.

255 is the max amount of grass that can be mowed before the level goal is met.
If more than 255 grass is placed on a level then the stage will be complete before fully mowed.
The total grass is shown in the title bar while editing.

Ctrl+S          Save changes to rom. You will be prompted where to save the new rom.

Right Click     Set spawn point
Left Click      Draw the current selected tile brush
1               Select mowed grass tile brush
2               Select unmowed grass tile brush
3               Select flower tile brush
4               Select rock tile brush
Page Up
or Up Arrow     Go to previous level
Page Down
or Down Arrow   Go to next level
NumPad-
or Left Arrow   Decrease width of current level
NumPad+
or Right Arrow  Increase width of current level
i               Toggle show images
g               Toggle show grid
a               Toggle flower animation