app nil YS YS app cons X XS YS cons X n__app activate XS YS from X cons X n__from s X zWadr nil YS nil zWadr XS nil nil zWadr cons X XS cons Y YS cons app Y cons X n__nil n__zWadr activate XS activate YS prefix L cons nil n__zWadr L prefix L app X1 X2 n__app X1 X2 from X n__from X nil n__nil zWadr X1 X2 n__zWadr X1 X2 activate n__app X1 X2 app X1 X2 activate n__from X from X activate n__nil nil activate n__zWadr X1 X2 zWadr X1 X2 activate X X 2.2 zWadr cons X XS cons Y YS app Y cons X n__nil activate n__app X1 X2 app X1 X2 prefix L prefix L activate n__nil nil activate n__zWadr X1 X2 zWadr X1 X2 activate n__from X from X zWadr cons X XS cons Y YS activate XS app cons X XS YS activate XS prefix L nil zWadr cons X XS cons Y YS activate YS true prefix L prefix L true Failed! NaTT certifiable-1.6