I remember, very clearly, the first moment that I saw Extend (now, of course, called ExtendSim). It was at a TIMS (a precursor of INFORMS) conference in 1993. At that moment I realized that I was looking at the future of simulation. This was an amazing program, a quantum leap in simulation technology. You could build a model by dragging and connecting blocks together. You could combine blocks together to create a single block. You could interactively change the model while it was running. You could create your own blocks. You could even program a block to do something when the simulation was not running. Wow!
At that point, I had already worked with a number of simulation programs (Siman, Slam, GPSS and more) but none of them could compare to the capabilities of Extend. What did I do? I asked for a job. After a rigorous interview process (I met everyone at Imagine that and did a little programming) and some pretty tough negotiations (they offered, I accepted), I started work. That was 17 years ago. The most amazing part of this story is that we’re still ahead of the pack. I’m even seeing some new simulation programs that look eerily like Extend did in 1993. I’ve heard some say that there has been no significant innovation in simulation software in the last 25 years. Extend came out in the 1980's - perhaps they are right.