Simplest Red-Green LED control circuit

I need a simple closed electric circuit with only basic components: 9V battery; Simple on/off master switch; 3 LEDs: Blue, Red and Green; 2 variable controls: A and B; Fixed resistors; Other simple standard components if required.

Expected behaviour when the master switch is on: Blue LED always on at fixed brightness; Increasing control A should direct current from green LED to red LED; Increasing control B should direct current back from red to green LED (overriding control A).

Min A + Min B = Bright Green LED + Dim Red LED. Max A + Min B = Dim Green LED + Bright Red LED. Max A + Max B = Bright Green LED + Dim Red LED. Min A + Max B = Bright Green LED + Dim Red LED.

by kelvin.stott
1 hour, 34 minutes ago
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