; and (II) cast shade on adjacent classroom windows in the school building to help reduce temperatures indoors and save cooling costs during the warmest parts of the school year. (vi) Natural playgrounds, which include natural and nature-based elements like rock gardens, sand boxes, stump logs, streams, living plants, and others that are integrated with the outdoor landscape and vegetation, and which— (I) will produce less heat than traditional playgrounds and equipment; (II) are more inclusive and accessible for children of all abilities; (III) allow children to learn about nature; and (IV) are more cost-efficient than traditional playgrounds. (b) Implementation grants (1) In general The Secretary shall award implementation grants to eligible entities that received a planning grant under subsection (a) and developed a master plan in accordance with subsection (a). (2) Applications An eligible entity that desires to receive a grant under this subsection shall submit an application to the Secretary at such time, in such manner, and accompanied by such information as the Secretary may require. An eligible entity may apply for more than 1 grant in order to complete individual schools in separate phases. (3) Use of funds (A) In general An eligible entity that receives a grant under this subsection shall use the grant funds to implement some or all of the master plan developed in accordance with subsection (a) by turning some or all of the outdoor spaces of the public elementary schools and secondary schools served by the eligible entity into living schoolyards. (B) Permissible uses An eligible entity that receives a grant under this subsection may use not more than 25 percent of the grant funds— (i) for professional development for school leadership, educators, and paraprofessionals related to outdoor teaching and bringing students outside for learning