Like many Tosa homeowners, I have several of these on the sidewalk outside my house:

I have had these X's for several weeks. Neither my neighbors nor I are sure what they mean. I think I know, but here is my mailbox:

As you can see, my mailbox is empty. The city has yet to send me anything to tell me what these X's mean. Unfortunately, I think it means something that will cost me money. Upon a quick search on the city's website, I found this item. However, it's pretty old.
So, do you have these same pretty X's in front of your house? Has anybody told you what they mean?