How about this: use a green acrylic with blue speckles (to represent water droplets on a grassy field), turn a clipless pen, and cast a roll-stopper that looks like a garden hose / hose with a sprinkler at the end? Or perhaps cast a clip where the body is a rod, and it ends with a smaller sprinkler shape?
No idea where you would find such an acrylic or how you would get that sort of shape cast. Perhaps get something 3D printed instead of cast? Shapeways can print in metals after all. I don't think you would want a clip made that way as I have no idea if their 3D printed metals have the necessary springiness for that, but it should be fine for a roll-stopper.
Huh, it just occurred to me that I've been working under the assumption that he works on garden sprinklers, when he could in fact work on indoor sprinklers - the kind that go off in a fire. Do you know which it is?