If I decide I want/need a fence this could be really fun. Recycled doors
DIY garden path. Take a multi picture frame to do this. Excellent idea!
Drill holes ever so slightly smaller than your marbles, so they will fit snugly and no adhesive needed. Sunlit, its sparkles! ... so be sure to pick your area on the fence where the sun goes behind it for the most sparkle...i.e., on the west side if possible, where the afternoon sun will shine on the backside.