A parlay is a series of all up bets on one ticket.It consists of 4 horses (dogs goats etc) at one meeting.
One unit consists of 11 seperate bets and costs (NSW) $11
we will call horses 1 2 3 4(in different races)
first 6 bets are all up singles
1 au 2 1 au 3 1 au 4 / 2 au 3 2 au 4 /3 au 4/
next 4 are trebles
1 au 2 au 3 / 1 au 2 au 4// 1 au 3 au 4/
2 au 3 au 4
next is accumulator
1 au 2 au 3 au 4

Hope this is clear enough. You can also have a 3 horse parly in NSW for a cost of $4. Same principle applies but 3 singles and 1 acculmulator.

Clear as mud ????
enjay