I found the the filled and unfilled flags on diagonal lines, the filled and unfilled boxes separated by a vertical line, and the dots and box separated by a ver

I found the the filled and unfilled flags on diagonal lines, the filled and unfilled boxes separated by a vertical line, and the dots and box separated by a vertical line difficult. I was running out of time, but thought it may have something to do with shifting and/or mirroring the position of the figures, and/or a base 3 representation but couldn't come up with a generalizable pattern. I didn't see anything which suggested that its better to attempt and fail or skip and complete as many as possible, which would definitely affect time management strategy.