I've been experimenting with different tips and I've had fun piping buttercream onto cakes instead of just spreading the icing on.
Here's a cake done completely with a petal tip:
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The top was ruffled in a circular pattern from outside to in.
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The side where piped with the "fat" side of the tip against the cake and the thin side angled slightly outward.
Clear as mud? ;)
Happy caking!
Teresa