Histo-Blocks is an interactive computer-based model. The model is a part of the ProbLab curriculum designed by Dor Abrahamson initially at Uri Wilensky's Center for Connected Learning and Computer-Based Modeling (CCL) at Northwestern University and later at UC Berkeley. The EDRL website features some of these latter models as relevant to our publications. We are grateful to the CCL for continued technological support and version updates.

Histo-Blocks is a model for exploring the binomial function. The random generator is a "4-Block," a 2-by-2 matrix, in which each of the four squares independently can be either green or blue. The 4-Block is thus just like four coins that each can land either on heads or tails, only that here you can easily adjust the collective chance of these four independent singleton events. For instance, you could adjust the model so that it will behave like four coins that each has a .6 chance of landing on heads. The model shows connections between the random generator's sample space, probabilities of its singleton events, its expected outcome distribution, and the binomial function.

This image features the interface of Sample Stalagmite. __The image is not interactive__. An interactive NetLogo Web version can be found __here.__ For best interaction with the model, please free-download NetLogo.