There are many factors affecting the patterns you can create.
Not all glass can be combined, owing to the chemistry involved in creating the different colours - although sometimes the effect of them reacting (like turquoise and vanilla shown here), can be spectacular.
Other effects can only be created with very high temperatures, working much hotter than is common for fusing. At these temperatures the glass may change its properties - for example many transparent colours become cloudy.
To achieve a desired result can require a lot of testing - small differences in kiln setup can make a BIG difference to the outcome.
The techniques I am using result in patterns with fine detail that you'll want to look at more closely!
You can revisit them many times and spot new features every time.