The chalk coastline

Source: an original fiction extract.

From the classroom doorway, the island looked almost real. Mr Vale had drawn its coastline across the floor in white chalk, steering around the legs of desks and ending beneath the radiator. Beyond the windows, rain blurred the playground. Imogen stood with the rest of the class while he explained that they had been shipwrecked and must decide where to build a shelter. He gave each group a folded map. Imogen's group chose the high ground immediately. She wrote their decision in large letters before anyone could suggest something less sensible.

The map showed a stream, trees and a broad beach. Imogen measured the distance between them with the edge of her pencil. A boy called Felix asked where the wind came from. She said it was only a game. They put their shelter on the hill because the sea could not reach it. Mr Vale came past and asked how they would carry drinking water uphill. Imogen drew a path. Felix said a path would not make the buckets lighter. At the next table somebody was arguing about whether coconuts existed on this particular island.

A bell rang, though it was not the end of the lesson. Mr Vale announced a storm. He scattered blue paper across the beach and laid strips over the lower ground. Groups whose shelters stood there had to move them. Imogen smiled at the safety of their hill until he placed a card beside it: strong winds, no trees. Felix did not say anything. She crossed out the word shelter and drew a smaller mark halfway down the slope. Another member of the group pointed out a hollow near the stream. For the first time, Imogen asked him to explain.

They spent the remaining minutes testing the hollow against each new piece of information. It was close to water, but not in the stream's bed; sheltered from one direction, but exposed from another. Nothing fitted without a disadvantage. When Mr Vale asked for their final answer, Imogen described the place and then the reasons it might fail. Across the room, other groups began adding qualifications to their own reports. The island had acquired so many pencil arrows and crossed-out labels that its original neat outline was difficult to see. Nobody asked who had won.

At lunchtime, the caretaker began mopping the chalk from the floor. Imogen waited for Felix by the door and watched the coastline disappear in grey streaks. Outside, water was collecting at the bottom of the steps. She suggested they shelter under the large tree, then looked at its branches moving in the wind. Felix pointed to the covered walkway instead. They ran there together. Behind them, the classroom was becoming an ordinary classroom again, but Imogen kept the folded map in her pocket, including the first answer she had crossed out.

Consider the whole source. Analyse how the writer structures the text to develop Imogen’s approach to making decisions. Support your explanation with references to the source.