i was outside looking south. there was a very bright white light, flashing about twice per second - no other colors - moving west to east below the cloud cover. it was larger and was going much faster than other aircraft. fast enough that each flash looked to be a dash. imagine sirius on a clear night, flashing and rapidly moving. this object made a sudden 90 degree turn south. in about two seconds it made a similar turn to the east, then south again, then back east for 3 to 4 seconds then vanished. possibly moving into and above the cloud layer. the cloud was not illuminated. i have seen others flying similar zig zag paths at high speed, but, never with this much cover or this size. being a quiet rural area, jets and other aircraft are easily heard. this one was silent.