Where could I start from to find the path to the green gun?

From what I understand, there is a green gun to remove green blocks, just as there is a blue gun to remove blue blocks. However, I have not found the room with the green gun. Could someone indicate which room I should start from to find the path to the green gun?

Here is my current map:

You are basically trying to find the room marked by the circle in below screenshot.

The location names are as follows:

• Stairway to Heaven (You can teleport here)
• The Butterfly Effect
• Jumping through Hoops
• Not enough Pieces
• Learning to Draw (where you will get the green gun)

There is a second way to get the green gun. From Leap of Faith, stare at the wall with the eye on it for about 15 seconds. Go through the opening after it disappears, then it's a straight-shot to the green gun (once you solve the puzzles :) )

Additionally, you can get the green gun in the rooms immediately following the blue one, if you're clever enough to open the door with four slots in 'The Final Hurdle'.

If you're having troubles doing this, see:

• How do I get through The Final Hurdle with 3 cubes?
• There are 4 slots but I have 3 blue cubes. How do I open this door in 'The Final Hurdle'?