@height = 6
@jmp_size = 3
@walls = {0=>{0=>0, 1=>0, 2=>0, 3=>1, 4=>0, 5=>0, 6=>1},
         1=>{0=>0, 1=>1, 2=>0, 3=>0, 4=>1, 5=>1, 6=>0}}
@position = 0
@current_wall = 0

def progress
  while (@position < @height) do
    (@walls[@current_wall][@position+1] == 0) ? @position++ : jump //No idea why this isnt working
  end
end

def alternate
  if @current_wall == 0
    @current_wall = 1
  else
    @current_wall = 0
  end
end

def jump
  alternate

  @position+=@jmp_size
  if @walls[@current_wall][@position] == 1
    @position-(@jmp_size+1) and alternate
    jump
  elsif @position > @height
    puts 'YES'
  else
    progress
  end
end

progress