RTGProblem85/Solution

 

leads to this seki (one eye each). White gets 1 point by playing at a near the end of the game.

 

here is a serious mistake. Black may fight the ko or...

Much better for Black  

...choose this line. 4 points each and Black' s wall has been strengthened in sente.

White is alive  

allows White to live with 7 points, though the top edge is sealed in sente. White needs another move at "a" near the end of the game.

Mistake by White  

This is a mistake; Black makes a seki in sente.

White lives with points  

If it's White's move, here turns the corner into 10 points territory.