The flight instructor was demonstrating a short approach and touch-and-go landing to the student pilot in a complex airplane. During the final approach, the flight instructor was unable to correct for a quartering tailwind and the airplane landed sideways on the left main landing gear. The flight instructor stated that "[the landing] felt a bit unusual, but the approach had been stable and the landing wasn't that bad..." The airplane took off and the landing gear would not retract. After troubleshooting the problem and declaring an emergency, the flight instructor landed the airplane with an unsafe landing gear indication. After touchdown, the left main landing gear collapsed, and the flight instructor lost directional control. The airplane impacted taxiway lights and came to rest upright adjacent to the runway. Postaccident examination showed the airplane sustained substantial damage to the left wing. Further examination of the left main landing gear and wing revealed overload damage to the landing gear wing attachment. The flight instructor reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation.