There are many ways you can arrange distance intervals.
Normally, you would choose the longest distance in the set to be just within your ability or just a little above it. You would add other quantity and quality requirements to the set to make it challenging in just the right amount for the system you intend to strengthen.
Usually, when written this way, there is some sort of passive or active rest assigned between the repeats.
When designing your set consider both the longest repeat length, and the total distance of the set when you add up all the repeats.
Straight Set
5x 100
You can compare more easily from repeat to repeat as you get more tired.
Ascending Ladder
25+ 50 + 75 + 100
Start when it is easy (according to distance) and gradually gets more tiring. Look for your failure point along the way.
Descending Ladder
100 + 75 + 50 + 25
You might start with a longer distance but easier quality requirement, then as distance decreases you increase the quality requirement – it gets easier in one way but harder in another.
Pyramid
25+ 50 + 75 + 100 + 75 + 50 + 25
You can break up a long distance into these pieces and though you are very fatigued toward the end, the repeats get smaller, giving you a psychological boost.
Fractional
(4x 25) + (2x 50) + (1x 100)
You can compare the difference of how more or less rest affects your performance – the total distance stays the same but rest is decreasing.