The students had to tread carefully.
They were, after all, on a minefield.
But its explosive potential was imagined, not real, and part of a series of leadership challenges at the intensive Youth Institute Kick Start programme.
It was run at the Ashburton Racecourse by retired teacher Ray King, with input from police officers, financial advisers, business leaders, and Ashburton College head boy and girl Caleb Livingstone and Connie Davidson.
The school leaders prepared the leadership challenges; Miss Davidson laid out a tarpaulin and told students that some squares were safe and others unsafe.
Only she knew.
She invited course participants to come forward.
They trod carefully; each was nervous.
The aim was for one student (all selected from district schools for their leadership) to find a safe way across the “minefield”.
Some did, and soon they were advising fellow students: “Left, right, diagonal”.
Elsewhere, Miss Davidson took one student from a group, selected another to lead a hand game, then brought the first student back to work out who was leading the others in the hand game.
It was not easy.
Then they formed themselves into a human tangle: arms linked, and then asked them to untangle themselves.
The Kick Start programme runs until today (Thursday), and includes sessions on leadership with mayor Donna Favel, with local business leaders.