posted this teaser pic about 5 weeks ago. I can now reveal it was.....
buy sheets of it here (scroll down - no affiliation). If you didn't buy sheets of it you'd just need to be a bit more cretive with the trouser stuff but it would still work.
I played around with some fonts first to get an F I liked but then just ended up drawing one freehand. I cut the webbing (which has paper on both sides) to the right shape and ironed it onto my dotty fabric. I then cut the fabric to the right shape around it and ironed it onto the hippo fabric. I think that would hold it without the need for sewing but for neatness I went round the edge with a small zigzag stitch in a suitable colour.
Did I stop there? Never. One of the gorgeous tutorials I've been gethering on this page (also in top menu bar) was calling to me....bunting.
followed this tutorial. Except I used a piece of ribbon instead of bias binding.