My faithful helper and I gathered as many of my crosses as we could find (there are probably more, but I can't remember where I stashed them), and arranged them on a piece of plain white paper.
Once we had them arranged, Aaron and I traced around each cross.
Then we measured down from the top of each one and made a mark where each nail needed to go.
After marking each nail spot, we moved all the crosses aside. We used painter's tape to hang the paper on the wall in the hallway. We drove the nails directly into the paper on the spots we marked.
I left a little space in the bottom center to add another cross, in case I find one at a garage sale soon (or I'd find more tucked away in a closet somewhere.) Because if I hadn't left room, I'd be sure to fall in love with one at a yard sale and have no place to put it.
So there you have it. In less than half an hour, with a little assistance from a very helpful eleven-year-old (who didn't realize I was sneaking in a math lesson by making him measure and mark the nail spots), I now have all my crosses on display instead of sitting in a box somewhere.