Logic models. Models can be encoded using simple Boolean logic (nodes may accept only true or false value), Bayesian probability (node values represent likelihood of events), or fuzzy logic (nodes have 'variable degrees of truth'). Depending on the availability of time-resolved data, these can be simulated to describe the system at steady state (one or a few selected time points), or dynamically (time course as a discrete sequence or as a continuous function). Solid red lines show methods implemented by the CellNOptR toolkit. ODE, ordinary differential equation.