My center is R11-c11, c13, & c15, R12 c12 & c14, R13 c11 & c15, R14 c12 & c14, and R15 c11, c13,& c15. And yet it tells me it is invalid. What am I missing? It completes as finished.
Never mind. Played it two more times and got it on the second time. Each time I got to end all squares were covered but there is only the one end. WOW.