Made to been seen at high speeds, these colorful patterns intentionally form a sequential whole when experienced by commuters in adjacent railway cars.

Katharina Grosse (with photos by Steve Weinik for the City of Philadelphia Mural Arts Program) conceived of this seven-section series, dubbed Psycholustro, as a way to engage everyday travelers with a project that addresses their in-motion perspective and the passage of time.

Grosse, a German artist based out of Berlin, targeted different sites with different bright colors, in some cases covering up existing graffiti on buildings or walls (with the expectation of re-tagging by other artists).

Lime green lights up an abandoned warehouse while bright orange highlights multiple structures and exposed rocks.

In a potentially controversial move, however, a purple area covers not only piles of rocks but also sections of nature, including grasses, shrubs and trees.

Grosse describes her project as something that “shifts your notion of size through movement” seeming huge from up close but to scale when you pass it by from your seat on a train.

Stephen Gardner, an Amtrak vice president, explains the project’s impetus: “There are some things that we can do better than other competing modes of transport, and that is to provide the traveler with a deeper engagement with the diverse landscape. One of our taglines is, “Enjoy the Journey.'”