One of the coolest “illusions” I’ve seen on cakes is the “Basketweave” piping technique. I love it because, done right, it honestly does look like the icing or frosting has been woven!
As you can see from the Amazon image of a typical basketweave tip (a generic brand, Size 2B tip) at the left, the edge on at least one side of the tip has a striated or serrated type of edge to give it a “ribbed” look. If you apply the icing with the SMOOTH side up, you will have a smooth, rather than ribbed look.
Note that the Wilton brand, #48 (larger) Basketweave tip has the serrations on BOTH sides of the tip.
There are basketweave tips in additional sizes as well to help you vary the size and look of the piping.
For example, a Wilton Basketweave Icing Tip #46 is a little smaller than a size #47, which is a little smaller than a size #48 (you can see these below)
The LARGER Basketweave tip is VERY helpful for creating the illustion that the cake itself is the basket. That is, if you look at the Amazon illustration of the #47 tip (Wilton) above, picture the ENTIRE cake encircled by that amazing pattern! If you look at this brief (less than 3 minutes!) cake decorating video on YouTube, by Wilton, you’ll see exactly what I mean.
As with anything, PRACTICE makes perfect!