A portable golf set my kids and I designed and built for impromptu guerrilla games on demand- any park, any time.
Supplies included about 30 small printed sheets of felt and 18 sheets of plain white felt, and 18 3/4-inch wooden dowels that were 36-inches in length. We raided my sewing box for contrasting colors of embroidery floss- The whole project set us back about $25 a bit less than going out for mini golf. The flags convert to banner garlands which we'll decorate the play room with when the winter rains start up.
Step 1: Laying out the flag design
First thing I did was to cut a template out of paper which would get one full flag out of a sheet of felt. Standard felt sheets are 9 by 12 inches. You could use another type of fabric for this project,but we like felt because it is stiff and the flags stand up straight making the numbers easy to read from a distance. If you used a softer fabric, like jersey cloth for example, you could iron interfacing between the flag layers to make it stand up.
I also marked out 7 one-inch parallel lines onto the template. These will be traced on the white felt backing to show where to slide the dowels through. You don't need to be precise on the placement of these, but I put marks at 3/4 of an inch,1 1/4 inch,2 1/2 inches, 3 inches 5 1/4 inch, 5 3/4 inch and 7 inches. Make sure your slits are at least 1/2 inch from the vertical flag edge.
Trace the flag template onto18 sheets of colored felt and 18 sheets of white felt.