gri software package provides a language for scientific illustration, you can install in your Debian 8 (Jessie) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install gri
gri is installed in your system.
Make ensure the gri package were installed using the commands given below,
$ sudo dpkg-query -l | grep gri *
You will get with gri package name, version, architecture and description in a table
| Distro | Debian 8 jessie |
| Section | Science |
| Package | gri |
| Version | 2.12.23-8+b1 [s390x], 2.12.23- |
| Description | a language for scientific illustration |
| Sub Section | Science |