We have different ways of keeping warm in Japan. Air conditioners (that also heat rooms... so it is a bit strange to hear someone ask if I'm cold and want the air conditioner turned on. The host means heat.) We have kerosene space heaters. We have spot electric heaters. The most traditional style of heating is kotatsu which is a low table with a heating element in it. The whole thing is covered by blankets and quilts so that the lower half of your body is warm while the upper half freezes.
And yesterday when visiting the pre school, I asked if I could take a picture of the principal's foot warmer. She has a very elegant foot warmer! It is a large heavy thing that sets under her desk. It is electrically heated and there is a large slab of rock at the bottom that warms first and then keeps the heat. The wooden container must be insulated too because it keeps the legs very warm. And when the principal sits at her desk with her feet inside the heater, she lays a blanket and a lap quilt over all and the heat stays completely trapped.
I really like the looks of this foot heater but I've priced them and they are very dear... If I did a lot of desk work I might splurge for one of these! But I only catch small bits of computer time during the day and even when knitting and quilting I seem to be up and about quite a bit.
Thank you Principal N for letting me crawl around under your desk taking pictures.