Lighted objects "dancing" and performing seemingly impossible aeronautic maneuvers

Passenger aircraft cruising at FL34,000. I was a crew member that entered flightdeck mid-flight. Two other crew members pointed out the 4 lights they had been watching for 45 minutes. Lights flying in circles vertically, horizontally as well as tight zig zag patterns, then flying straight upward. The circular motions were like a dance. No regular patterns, but incredibly fast maneuvers. The lights would disappear and reappear occasionally. The altitude of the objects was unknown, but they were so high that they never left our view during that time. I watched them for 15 minutes before allowing another crew member to observe as well. As our pilot said, "no aircraft exists that can perform those maneuvers." Four crew members witnessed.