This sentence should be normal.

This sentence should be bolder than normal.

This sentence should be bold.

Whatever this line looks like...

...this line should look bolder (or the same).

This sentence should be normal.

This sentence should be very light.

This sentence should be slightly bolder (or the same).

This sentence should be slightly bolder again (or the same).

This sentence should be slightly bolder still (but not the same).

This sentence should be the most bold (and maybe the same as the last one).

This sentence should be bold. This sentence should be normal.