大家好！
最近在阅读Paul A. Samuelson的一篇论文《An exact consumption-loan model of interest with or without the social contrivance of money》，其中有这样一段话：

“... the last case(利率大于0) is usually considered to be technologically the most realistic one: that is, machines and round-about processes(rather than rabbits) are considered to have a 'net productivity', and this is taken to be brute fact.”

有两个问题：
1、这里的round-about processes，如何理解，我查询了wikipedia中有一个roundaboutness（ http://en.wikipedia.org/wiki/Roundaboutness ） 但是没太看明白，回到论文的上下文也不太清楚；

2、这句话我整体也没太看懂，一些关键点已经用蓝色标记出来了。请高人能否谈谈自己的理解。

谢谢大家了！