[T]his was in any case a penal colony where extraordinary measures were needed and that military discipline must be enforced to the last.

This passage acknowledges and identifies the nature of the penal colony at the beginning of the story. As a place where prisoners are isolated and imprisoned away from other citizens, it is, by nature, a carefully secured place with strict rules and regulations. The fact that a military runs, supervises, and controls the colony implies an even greater level of rigor in the enforcement of the rules in place. The use of the word “extraordinary” seems to support the use of the apparatus the Officer demonstrates at first. However, as the Traveler learns more about the device and the system it represents, he understands how the extraordinary measures are, in fact, horrifying and barbaric. The extraordinary measures, then, foreshadow the means through which the system will ultimately be challenged. Although it’s the Traveler who instigates the change, it is the extraordinary action of the Officer who releases the condemned man and takes his place in the apparatus that signals the downfall of the old system within the penal colony.

[T]he administration of the colony was so self-contained that even if his successor had a thousand new plans in mind, he would not be able to alter anything of the old plan, at least not for several years. And our prediction has held. 

The world of the penal colony is shown as an isolated dictatorship when the Officer describes the inability of the new Commandant to change the old system in the beginning of the story. The old Commandant, with the help of the Officer, constructed a “self-contained” and fascist system that he predicted would ultimately be challenged. The careful design he conceived, put in place, and expected the Officer to defend is indicative of a paranoia toward any threats to his way of running the colony. It is notable that in order to have any hope of making changes, the new Commandant felt compelled to invite a foreign guest, the Traveler, to come and render an opinion about the system the former Commandant put into place. The need for and presence of a respected outsider is indicative of how closed the penal colony system is. As the Officer boasts, the former Commandant’s system was so carefully crafted that it takes something dramatic and drastic, like the disapproval of an outsider, to have any chance of effecting any change.

[T]he glare of the sun in the shadeless valley was altogether too strong, it was difficult to collect one’s thoughts.

The valley of the apparatus symbolizes the system in which it is situated in this passage from the beginning of the story. It is described as sandy, and nothing grows, let alone flourishes there. It is surrounded by barren slopes of rocks, again indicative of the sterility of the location and the impossibility for anything to grow there. The disorientation inspired by the glare of the sun represents the inability to conceive of any escape or even any other way of life. The control over the people within the penal colony is so complete that it is “difficult to collect one’s thoughts” or conceptualize any alternative to the system in place. The relentless sun represents the light or knowledge of the injustice being perpetrated beneath it. It bears down on everyone, yet there is no possibility of any relief or respite. Regarding the setting through a Biblical lens, the site of the apparatus is a valley where the only shadow is death. The only release is through the brutal apparatus and the twelve hours, or term of sunlight, it takes the condemned men to die.