Funny you posted this tonight, the last few days at my work place (a large multi-building hospital) I always take a short cut to get to buildings and I cut through the shipping&receiving loading dock/laundry/housekeeping area and lately I've noticed 'drag marks' on the pavement while taking this short cut. I can't figure out how the drags marks are made at the hospital! But it got me thinking...drag marks don't necessarily mean a person was dragged, but could be a mop or even wheels on something (the marks didn't look like wheels as the liquid expanded on pavement, but I was thinking of what kind of traffic would leave a liquid trail in that area of the hospital). The pattern in your photo reminds me of how someone would swivel a mop maybe.