...Then, David deposits 90 QD and draws a $80 worth of ETH in crypto debt.
...Then he re-deposits that ETH into his original QD position, now holding a total of $180 in ETH collateral.
...Doing this allows David to draw another 70 QD.
...In summary, David is long $100 worth of ETH (his own ETH), but he owes $80 of ETH.
...Let's say ETH goes up 10%. The $180 of ETH in David's QD position is now worth $198, but his ETH loan ...was liquidated, so he lost 90 QD. He has 70 QD from it though, and can close his other debt by inverting some ETH into QD (good deal for SP if ETH keeps rising)...leaving him with 108$...but he chooses to stay
...So David started with $100 of ETH, which would've been worth only $110 holding it, but now he has $178, which means he experienced a 78% profit rather than a 10% one, these are only paper gains though, the best part is loss protection...Let's say ETH goes DOWN 10%. The $180 of ETH in David's QP position is ...now worth $162...he is dangerously at the brink of liquidation at 162/160 (90 + 70 QDebt) = 101% CR
...but his ETH loan can be paid back for $72 now: he borrowed $80 of ETH that's now worth 10% less
...So 18 QD is left over from his collateral for the ETH loan, after closing it out (90 minus 72)
...18 QD + 70 QD from the second mint of the QD position = 88 QD...it's now a good time to redeem these (provided that eventually ETH will go back up) because ETH can be "purchased" at a discount from other borrowers who are close to getting liquidated...protecting both them and David, re-depositing $88 of ETH into his QD position to be 250/160 at a CR of 156%
...So what now? You guessed it...borrow 65 more QD, we're back at the brink of death 250/225 = 111% CR
...Let's take another short out, pledge 65 QD, get $55 of ETH, put it in the QD position...305/225 = 136%
...ETH fell ANOTHER 10%, damn what a day, we lose 65 QD...QD position is still safe at 274.5/225 = 122%
...Now...wait or it...ETH is up 20%...329.4/225 = 146%...f**k this roller coaster, cash out, left with $104.4 :)