Universe today has satellite before and after photos of areas in Japan hit by the earthquake and tsunami
An update of the Sheparding asteroids article is provided by this site.
In space it is relatively easy to move quite large space rocks using solar sails, ion drives and other means. There are a lot of space rocks and a survey could be done to select the rocks that would have to be moved with the least amount of effort. Then once each asteroid is moved into place they would be locked into place. It could be easier to gather asteroids to make desired shapes instead of digging out a larger asteroid. Different sized asteroids could be used from 500 kg, to tons up to asteroids that are 100 to 1000 meter across
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