Anti-Climb Spikes for Cats or Birds

The is an anti-climb spikes to prevent cats or birds to stay on the window sill. This hopefully could prevent the pets to piss or shit on the flat surface. There are 3 versions tested. The 1st with higher spikes (20 mm) but smaller base diameter (4 mm) of the spike. The 2nd and 3rd version are with spikes height 15 mm and larger base diameter (5 mm). The 3rd version is covering a bit larger surface (1 more row added). The 3rd version is with the best test result and my cat would not like