Ja

ja is an esoteric programming language created by User:A. Twin language: Aj

Instructions

Instruction	Description
j	jump to cell numbered as the current cell and jump to the cell-th code command.
a	add current cell by 1

Example (Infinite Loop)(Set array to 1111111...)

aj

Computational class

a = +
j = < or > or [ or ]

This suggests that there *might* be enough power for Turing-completeness by emulating brainfuck or some variation of it.

However, because the translation depends on what values are in the cells, there remains quite a bit of work to show that you can achieve an arbitrary effect at an arbitrary point.