A single terrace can be made using the get altitude function.
Then use a conditional set to 'between' for an altitude range and whenever that criteria is met then set the output to the lower limit of your altitude range.
When the condition is not being met, thus exceeds the altitude defined in your range, you will end up with a big vertical stretched step and you want to avoid that.
To do so, subtract the altitude range from the output of the conditional.