so anyway you are to go to a beach and draw a convoluted coastline [with an isthmus or purse cove etc] in the sand. then take a rope and lay it along the coastline. mark on the rope approximately where you think you would be at noon each day for a month. now coil it up and you would have some type of rough record of time and distance.
now what if the important thing was not the distance. what if you were an explorer in 1800bc and the important thing was what you saw or encountered on land as you sailed by each day. record that and coil the rope.
it continues that you would have to know the order of the months [sides] via the dots apparently and ways to record sailing direction options/rules. it apparently explains the strange repeats on one side.