Stefanie Hiller 
Working with the geoboard. An action-oriented approach to the geoboard in elemantary school (2nd grade) [PDF ebook] 

Lesson Plan from the year 2009 in the subject Didactics – Mathematics, grade: 1, 2, Studienseminar Hamm, language: English, abstract: Theme of the series: ‘We work with the geoboard.’- An action-oriented approach to the geoboard by collecting a variety of experiences on plane figures, their properties and the congruence of surfaces to promote spatial orientation skills and the further development of visual perception skills.
Theme of the unit: ‘We discover different triangles on the geoboard’ – An active-discovering examination of the flat form ‘triangle’ through an exploratory approach to the 3×3 geoboard, in which the children stretch as many different triangles as possible and compare them with each other, with the aim of gathering further experiences on the congruence of surfaces, as well as promoting spatial orientation skills and the further development of visual perception skills.