You can use almost anything to do this but I would think the easiest thing would be to purchase a piece of plastic trellis. You can cut it into the shape you want if you don't like the rectangular way it comes. Depending on where you want to place it will drive how you put in place.
You can purchase 2X2 boards at the hardware store and either glue or tack them together, preferably with a nail gun, in an oblong style, to make it easier. Draw out your design first.
Here is a link to a dollar store trellis
https://www.youtube.com/watch?v=I2u8mi2XFT4
You can use almost anything to do this but I would think the easiest thing would be to purchase a piece of plastic trellis. You can cut it into the shape you want if you don't like the rectangular way it comes. Depending on where you want to place it will drive how you put in place.
You can purchase 2X2 boards at the hardware store and either glue or tack them together, preferably with a nail gun, in an oblong style, to make it easier. Draw out your design first.