An infinite strip with a symmetric pattern is called a frieze pattern.
There are only seven possible frieze pattern.
1. Translation symmetry only.
2. Glide reflection plus translation symmetry.
3. Reflection over a horizontal line plus translation.
4. Reflection over a vertical line plus translation.
5. Rotation (a half-turn about a point on the mid line of the strip) plus translation.
6. Reflection over a vertical line plus a reflection over a horizontal line plus translation.
7. Reflection over a vertical line plus glide reflection plus translation.
