Thinking about the name of this achievement is what helped figure out how to code this.
The task at hand is to double the input and output the result. Running all doubling calculations through a single node usually yields 160 cycles or so at best. Clearly unacceptable. However, running the doubling code through two separate nodes, or PARALLEL, should half the cycles. Once I realized this, writing the code to accomplish it wasn't too difficult.
I recognize my description is not the most in-depth. My hope is you can take the hints I've dropped and solve this from there. However, if you'd like to see the exact code I wrote, click on the spolier for a screenshot of my code running in 84 cycles.