Q.2. There are 3 points labeled X, Y and Z. Then there are other 3 points labeled 5, 6 and 7. The aim of the puzzle is to connect point X with points 5, 6 and 7, point Y with points 5, 6 and 7 and point Z with points 5, 6 and 7. While connecting the points you have to follow one rule - the lines cannot cross over each other.
There is no solution to it, if you consider 2 dimensions. It is impossible to join each of points X, Y and Z with points 5, 6 and 7 without lines crossing each other.
There is solution, if you consider 3 dimensions. Consider a circular base and a line perpendicular to it passing from the center. Now take any 3 points along the perimeter of the circular base as points 5, 6 and 7. Similarly take any 3 points along the perpendicular line as points X, Y and Z.
Now it is quite simple to join each of points X, Y and Z with points 5, 6 and 7 without any of the lines crossing each other.
The other possible 3D structure is Pyramid. Take points 5, 6 and 7 as vertices of the triangular base and points X, Y and Z along the height of the Pyramid which is perpendicular to the triangular base and passing through the apex.