Andru Kopelani, 12, and Megan-Stanley, 11, suggested including water features in the playground.
Given the school had an existing bore, that would be easier than for most schools.
In particular, they were keen on a rambling stream over rocks "reflecting the riverbed of Flaxmere".
The display by Maleta Pailate and Janet Vaiusu, both 11, was based on "loose parts".
The idea was to further develop the range of objects that children, particularly the juniors, could use to build with. "It's about letting them use their imagination."
About 130 people attended the open day, principal Matt O'Dowda said. They placed yellow dots on their favoured parts of the children's designs.
A great deal of thought had gone into how the outdoor spaces, including how they could be used by the wider community, O'Dowda said.
"It's about creating beautiful, challenging natural playscapes, grounded in Te Ao Māori."
The list of goals that the design needs to achieve is impressive but achievable, said O'Dowda.
"We want to include the community in this. As well as being a space that contributes to learning, we want it to reflect our rohe, our people, and to have spaces for different activities, including being somewhere beautiful for our whānau to connect.
"We asked ourselves, parents, teachers and the kids, what this could look like. We want it to be challenging for the children, but we also want somewhere where nanny and koru can sit in the shade and watch the kids playing.
"We want this to be an extension of our school community, for our wider community."
He said the design phase had been a valuable learning experience for the kids. "This is great project-based learning. They have researched, collaborated and shared their ideas on what they would like to see in our outdoor learning spaces."
And the learning continued, with the young designers helping their principal present their ideas to Hastings District councillors last week.
"They are great kids who have really understood each of the design elements and can talk confidently about their designs. The council was impressed."
That presentation saw the council commit to financially supporting the school's next step: the full design which will include a lot of feedback and collaboration.
That will inform the amount of money required to complete the project.
On the fundraising front, the school had enlisted the help of Te Puna Taiao, a charitable trust focused on making the best use of outdoor spaces in schools, particularly in areas of greatest need, and helping communities raise the funds needed to build the project.
O'Dowda said while the Ministry of Education would pay for the rebuild of the school, it relied on each school's community to design and fund the outdoor spaces.
"That's a very big project and we are rapt to have Te Puna Taiao on board to assist us with this side of it."
The ministry-funded school rebuild includes six classrooms, a half-court gym, music room, administration area, outdoor fale and kitchens.
