How can you differentiate between a geometric sequence and an arithmetic sequence

An arithmetic sequence increases at a constant rate.
A good example is multiples of 3
3 6 9 12 15 18
Each number equals the next number by a difference of three.

A good example of a  geometric sequence is the powers of 2
2 4 8 16 32 64 128
Here, you see, the difference between the numbers is constantly increasing.