Can I, somehow, display my MacBook Air on my 21 inch iMac?

[iMore Question]

I made a really stupid mistake and assumed I had a 27 inch iMac, so I bought a thunderbolt cable to enable Target Display Mode, and when it didn't work I decided to measure my iMac and realized it was the 21 inch (thankfully the cord was $6). Anyways, I was wondering if there is still some way to mirror/display/extend my MacBook air desktop to my iMac? Thanks

 

[kch50428]

Apple - Remote Desktop