The "indicating what parts of their programs are costing the most" made me think of the color scheme when working in cython: white (C-fast), yellow (slow).

The "indicating what parts of their programs are costing the most" made me think of the color scheme when working in cython: white (C-fast), yellow (slow). http://docs.cython.org/src/quickstart/cythonize.html#determining-where-to-add-types http://docs.cython.org/src/quickstart/cythonize.html#determi... of course it doesn't tell you anything about the speed of the C code, but I find the line coloring to be a nice UI for showing computational cost.