Chromatin has a complex spatial organization in the cell nucleus that serves 
vital functional purposes. A variety of chromatin folding conformations has been 
detected by single-cell imaging and chromosome conformation capture-based 
approaches. However, a unified quantitative framework describing spatial 
chromatin organization is still lacking. Here, we explore the "strings and 
binders switch" model to explain the origin and variety of chromatin behaviors 
that coexist and dynamically change within living cells. This simple polymer 
model recapitulates the scaling properties of chromatin folding reported 
experimentally in different cellular systems, the fractal state of chromatin, 
the processes of domain formation, and looping out. Additionally, the strings 
and binders switch model reproduces the recently proposed "fractal-globule" 
model, but only as one of many possible transient conformations.