It is. Most matter we think about is what you would call a space-time worm. A pattern of 4d continuous worms interweaved together. If at a given time the patte

It is. Most matter we think about is what you would call a space-time worm. A pattern of 4d continuous worms interweaved together. If at a given time the pattern stops, we consider that the structure broke. Matters that spontaneously break are unstable. Materials we call impossible are only impossible under these conditions : stable a d continuous in time. The idea of matter that may be discontinuous in time but still display some characteristics of stable solid matter is pretty new.