Technically, America does have more than two parties. Learn about the others here: America's Weird, Small Political Parties Explained - TLDR News
'Osama bin Laden' campaigns in Brazil -- Brazil Campaigns
If we had multiple parties in the US it would probably look like this (reading)
Voting Systems and the Condorcet Paradox and Voting Systems and the Condorcet Paradox | Infinite Series (advanced-- is democracy mathematically impossible)
FairVote - this website is from a group that "… is a nonpartisan organization seeking better elections for all. We research and advance voting reforms that make democracy more functional and representative for every American. FairVote is the national driving force behind advancing ranked choice voting (RCV) and proportional RCV" Ranked Choice Voting page is here.
The Best Electoral System Test (BEST) allows those involved in the debate on electoral system design to explore the characteristics of twelve common electoral systems in an interactive way. Users can set their priorities for 16 properties on a scale and immediately see a list of best matching electoral systems.