This [script](https://osf.io/ufswb) creates a Webnucleo zone XML file with exponentially (with zone number) declining temperature and density. It also sets the initial, uniform mass fractions.
To use, first download the file by typing
**curl -o create_exp_zone_xml.py -J -L https://osf.io/ufswb/download**
Then create the zone XML. In this example, create 100 zones with initial temperature T9 = T/10^9 K = 2 and density 500 g/cc, an e-folding for the temperature and density over 30 zones, and initial mass fractions of <sup>4</sup>He and <sup>56</sup>Fe each of 50%:
**python create_exp_zone_xml.py zone.xml --t9_0 2 --rho_0 500 --n_zones 100 --fall_off 30 --init_x he4,0.5 fe56,0.5**
The output is in the file *zone.xml*.