Plan: to confuse a friend, works better when the friend drunk a bit. The idea is to construct a 18x18, which looks like a 19x19.
Of course, you could construct a "normal" 18x18, but I tend to love the idea of all the Star points in roughly the "correct" places.
How to do that: 1) make 4 intersections with different sizes. 8 rectangles: 72*72 (pixel); 9 rectangles: 72*68 9 rectangles: 68*72; 9 rectangles: 68*68
2) Put the Starpoints in such a way, that it looks "right". Well, it never looks perfect. But if you donīt put to much attention or you are drunk/ distracted...
3) Play and enjoy confusion. If your friend is not confused, next game take white, no Komi and play mirror go. Remember: The star points can confuse yourself! Pay attention to where to put the Stones. Works well with the 1st of April.
4) Hints for tricking: If the friend is a bit aware, something could be wrong, and some point you could say: "Ya, I constructed it, I took somehow wrong measurements. But ya, I was a bit drunk." Also you might count from the right to the middle: "1, 2...10." ... and then from the left to the middle: "1, 2...9. Together: 19."