def(markvisiblefromleft) /.+/ => (
	/^/ => { "" set(highest) }
	/./ => {
		_ _ ord 16 % get(highest) > if 
		! increase code points of visible trees by 16 
		{ ord 16 % set(highest) 64 + chr }
	}
)
def(rotate) #( ! clockwise
	fx { empty(lines) }
	/.+/ => fx { _ push(lines) _ len set(width) }
	{
		get(width) times {
			count(lines) times {
				pop(lines)
				copy 1 skip cons(lines)
				1 take 1 rpad
			}
			"\n"
		}
	}
)

#(
	{ _ 4 times { do(markvisiblefromleft) do(rotate) } }
	/\d|\n/ => ""
	{ _ len } ! count remaning non-digit trees
)