This simulation demonstrates Delta and Wye conversions in circuitry. The circuit on the left is an example of a delta while the one on the right is a wye example. The far right resistor with 1k on both circuits make it so the wye connection doesn't node b and c connect, it also helps to actually show the equivalent resistance between both circuits. Feel free to use this as part of conversion practice. Include the 1k resistor as part of your practice problems.