Not much shop work involved, but I did go through some iterations in my mind before deciding on the end result
Last week I put up flags for Memorial day as I had in years past, but we had just renewed/replaced the bedding planting which required new placements. In front of the main bed I planted the flags in the grass, but on the side there is no grass in front so I had to punch holes in the weed membrane and plant the flags in the bed itself:
I wanted to preserve the hole locations so that I wouldn't push new holes even year (defeating the purpose of the membrane), so I dropped landscaping spikes into the holes when I removed the flags and started to figure out how I would find the spikes on July 4th. I would keep the spikes (which have a smaller diameter that the flag shafts), but wanted something on top so I wouldn't have to use the metal detector to find them. Plastic lids? Some kind of surveyors marker? Aha! I had it:
I used a step-drill to enlarge a hole in a Wiffle™ golf ball to pass the spike head, inserted the spike and voila:
Now I can find the holes, and the balls don't look to out of place in the bed.
Then I realized that I had come up with a novelty item worthy of Johnson Smith or the Har-De-Har Hut. Plant them amongst a handful of Wiffle™ golf balls and invite your friends to take a swing. Cut a slit in a yellow tennis ball for the spike head, drive the assembly into firm ground, toss another tennis ball for the doggy to chase and watch the fun. I'm going to get rich!