This script is an example of how to create a constant gradient across multiple svg objects, such as bars in a bar graph. Based off an example by Mike Bobstock, modified to extend across multiple bars.
Data presented in example are various meltal's melting points. Data collected from: The Engineering ToolBox, 'Metals - Melting Temperatures', https://www.engineeringtoolbox.com/melting-temperature-metals-d_860.html. Collected August 25th, 2018.