Problem 1: query by tag, execute, annotate, query by example and pruning
To make sure you know how to search versions in the history tree of Vistrails do the following simple task:
1) In the History view locate the version tagged "EX1". Execute this version and annotate it with the name that appears in the visualization.
2) Query by Example Delaunay
Problem 2: design pipeline from an image
From the root version on the History View design a pipeline to reproduce the image below. Tag the resulting pipeline with label "Problem 2".
1) From the root version on the History View design a Vistrails pipeline equivalent to the VTK pipeline equivalent to the code
translate the C++ VTK source code into a Vistrails/VTK pipeline
2) locate the only version in the file that has a module X connected to a module Y.
Note that there are many versions in the vistrail. You should use the