The Eight Amendment to the Constitution of the United States declares

Excessive bail shall not be required, nor excessive fines imposed, nor cruel and unusual punishments inflicted.

(Underscore mine.) The constitution of the state of California has a much more complex discussion of bail; but its Article 1, §17 declares

Cruel or unusual punishment may not be inflicted or excessive fines imposed.

(Underscore mine.) Plainly these words are an adaptation from the US Constitution.

The replacement of and with or was apparently to indicate that cruel punishment were not to be deemed acceptable simply by virtue of being usual. Indeed, Article 1, §17 of the constitution of the state of Florida used to declare

Excessive fines, cruel or unusual punishment, attainder, forfeiture of estate, indefinite imprisonment, and unreasonable detention of witnesses are forbidden.

(underscore mine) and the state supreme court made just that interpretation in cases of the death penalty. (The section has since been radically revised.)

However, a hypothetical problem arises from the replacement. Just as cruel punishment is not acceptable regardless of whether it is unusual, unusual punishment is not acceptable regardless of whether it is cruel. And, if most or all prevailing punishments were cruel, then punishment of any other sort were unusual; and unusual punishment has been forbidden. Thus, under such circumstance, all punishment were forbidden!

This problem may not be merely hypothetical, in the context of problems such as prison over-crowding. (Of course, when push comes to shove, lawyers and judges tend to shove logic out the door.)