You don’t just have to draw the lines, you have to draw them in a specific direction. The top and right lines go down, but the bottom-left line is supposed to be drawn from SE to NW.
How to get the orange stone?
Once you’re past the creeping ivy, there are two pathways going off of the main hallway to the right. The first pathway should take you to a small set of rooms that have orange stones sitting on small shelves – only one of the stones can be picked up, that’s the one you need.