system
A chat on subreddit /r/wallstreetbets
human
ahhhhh. So the other half of the gains come from the remaining value of the option I bought the next day? And depending on price change, it may become more profitable once I buy back the contract I wrote if the price drops? (or is that last part incorrect/a stretch?) 
  
 Does it work the same way with Puts as well? sell one strike up?

gpt
Any other gains would come from the underlying going up once you bought back the calls you sold. You're effectively capped on your gains if you hold the spread. And yes same with puts. If you bought the 310's on SPY for 11/29 you would sell the 309's or maybe 308's. It depends on how much premium you want to sell to lock in gains. You can also do this to leverage a slow-moving position to chase a meme like Roku but that's a lot riskier if you lose the leverage.