"red-white-and-blue Czech flags"

Czech flag
Public DomainCzech flag
The simple design of the Czech flag since 1920 (save for the period of the Nazi occupation from 1938 to 1945) has consisted of two equal horizontal bands -- white on top, red on the bottom -- with a blue isosceles triangle intruding from the flagpole edge.

The red and white came from the ancient coat of arms of Bohemia. Because the result too closely resembled the Polish flag and had the same colors as the Austrian flag, the blue wedge was added in 1920.