In sequencing, one of the most creative techniques is to combine two drum or percussion loops. The results are often unpredictable, but unexpected creative avenues can often spring from chance interactions.
Unless you are really lucky, the two loops will not be of the same duration. This means that although you can cycle one easily, the other will either be shorter and therefore finish too soon, or it will be longer and will not fit in the available space. Let's assume the second loop is shorter.
If you play the two loops together, apart from them not ending at the same time, you will undoubtedly notice that there is a terrible jumble of beats.
But this is easily remedied. Place the insertion point of your sequencer exactly on the second visible beat of your second loop, and divide the loop. Some audio sequencers make this easier than others so you might have to do battle with the technology just a little.
Repeat this process for every visible beat. Sometimes a beat can have a little 'upswell' just before the main hit. Usually it is best to cut immediately before the main hit.
Once you have sliced the loop into separate beats, you can move them around so that they match up with the beats of your first loop. Sometimes, there will be an 'in-between' beat in your second loop where there is no beat in the first. In this case, guess! A little bit of tweaking will help you find the right place.
When you have done this you will be able to cycle both loops in sync, and you will hear a pattern of beats that it is almost guaranteed no-one has heard before.
The second loop will be gappy, and you will be able to hear this clearly if you solo it. But most times this doesn't matter in the least.
If things don't work out too well and the result is not usable, it might be worth some more experimentation, including dropping some beats if necessary.
Otherwise, simply start again with different source material. This technique is a powerful creativity generator and if it doesn't work first time, it's guaranteed that it will spark off more ideas for you to think about.
There are of course other ways to combine loops…