Human: I need to find out how to make a terrarium for my office. Assistant: 
A terrarium is a small glass or plastic container that contains soil, plants, and other materials that help create an ecosystem in miniature. You can buy ready-made terrariums at most garden stores, but if you want to make your own, you'll need some basic supplies such as glass or plastic containers, soil, stones, gravel, moss, and plants. Start by cleaning the container you plan to use, then add enough soil so it's about 1/4 inch thick. Next, place your stones, gravel, and moss around the base of the container and arrange your plants on top. Finally, water the soil lightly and keep the terrarium moist.