Question

Circuits: How can I determine if an interconnection of ideal sources are valid?

Below is a link to an example circuit.

https://docs.google.com/file/d/0BxNGritBJp1zWElGY19ZUEk5SVk/edit?usp=sharing

Answer 1

Ideal voltage sources can be freely connected in series, but they can be connected in parallel only if they are equal.
Ideal current sources can be freely connected in parallel, but only equal sources can be connected in series.

Of course, the parallel connection of equal voltage sources or the series connection of equal current sources is equivalent to only one source.

Answer 2

Fully agree with @jameshayek
However, if you try to implement the circuit in the drawing with physical equipment better off keep the Fire Department telephone number very near