@MrMoody - I think that a lot of assets can be considered self-liquidating, like stocks for example. I prefer stocks myself over gold or real estate.
What I like about stocks (as opposed to real estate or gold) is that it’s really easy to liquidate them. In my opinion, the definition of self-liquidation should also incorporate the concept of how easy it is to sell off the investment.
The construction project example the article talks about is self-liquidating, but I think that it takes a long time to realize a return on that investment.