In the spirit of St. Patrick's Day (or, at least, in the pop culture spirit of it) I made a small 3d printable tie that is semi-flexible due to a .25mm thick bottom layer that holds the shamrocks together. The hole in the top bit is there to run a rubber band through so it can be secured to your collar, as a tie should be. If I had time to re-design it, I'd integrate a clip onto the back of the top 'rock so it really be a print'n'wear item.
I designed it to be 250 mm long because that's as big as I could fit on my 200mm by 200mm print bed diagonally, but you can definitely resize it and add more shamrocks if you have a bigger printer.
Here is the TinkerCad link if you want to edit it yourself: https://tinkercad.com/things/gpgrQD4H81R