The Virginia Plan was a proposal by Virginia delegates for a bicameral legislative branch. They proposed that both houses of the legislature would be determined proportionately. People would elect the lower house's representatives and the lower house would elect the upper house's representatives. The representation would be based on population or wealth of the states.
Another proposal, and the one contained in the U.S Constitution and it still remain today was the separation of power in three branches of government: legislative, executive, and judicial.