When is a pot not a pot ?

My lifetimes obsession of gardening at this time of year reaches fever pitch. My garden is tumbling over with plants and I don't have enough room really for anymore. But you see something new or unusual and you have to start becoming more creative about what you are using to house your plants in. So I have decided on a two prong attack more plants means more pots. I have lots of old junk that I keep for a rainy day so I have started planting in anything that has drainage and will hold soil and plants. First was my mums beloved Jones machine that stopped working a while ago but I kept it in my studio as it holds sentimental value. I didn't want to throw it out so cut off the top to use as a wonderful plant pot. I love it! I have been growing veggies in old tins of food, geraniums in a row of old handbags and cress in dolls heads. So I ask the question when is a pot not a pot?