Test passes if there is no red visible.
st | st | st | st | st | st | st | st | st | st | st | st |
st | st | st | st | st | st | st | st | st | st | st | st |
st | st | st | st | st | st | st | st | st | st | st | st |
st | st | st | st | st | st | st | st | st | st | st | st |
st | st | st | st | st | st | st | st | st | st | st | st |
st | st | st | st | st | st | st | st | st | st | st | st |
st | st | st | st | st | st | st | st | st | st | st | st |
st | st | st | st | st | st | st | st | st | st | st | st |
st | st | st | st | st | st | st | st | st | st | st | st |
st | st | st | st | st | st | st | st | st | st | st | st |
st | st | st | st | st | st | st | st | st | st | st | st |
st | st | st | st | st | st | st | st | st | st | st | st |
st | st | st | st | st | st | st | st | st | st | st | st |
st | st | st | st | st | st | st | st | st | st | st | st |
st | st | st | st | st | st | st | st | st | st | st | st |
st | st | st | st | st | st | st | st | st | st | st | st |
st | st | st | st | st | st | st | st | st | st | st | st |
st | st | st | st | st | st | st | st | st | st | st | st |
st | st | st | st | st | st | st | st | st | st | st | st |
st | st | st | st | st | st | st | st | st | st | st | st |
st | st | st | st | st | st | st | st | st | st | st | st |
st | st | st | st | st | st | st | st | st | st | st | st |
st | st | st | st | st | st | st | st | st | st | st | st |
st | st | st | st | st | st | st | st | st | st | st | st |