Pot's Collection
Here are two pots and a tray to keep the pot in. Each of these can be used individually or as any combination that suits your fancy. I have designed one pot smaller than the other with a specific intention. The smaller pot when placed inside the larger pot with a spacer at the bottom [ ideally in the centre where the drain should be] leaves enough space around it to pour a mixture that will set to form a pot, thus acting as a mould. Once the mixture hardens the two pots can be separated.
ps: I didn't put a drain in any of the designs because it was more practical to drill a hole that to close one in case it was not needed.