You can do it by cutting and folding a sheet of clear acetate or similar from a net like this: https://wp.optics.arizona.edu/oscoutreach/wp-content/uploads/site

You can do it by cutting and folding a sheet of clear acetate or similar from a net like this: https://wp.optics.arizona.edu/oscoutreach/wp-content/uploads/sites/75/2018/04/IMG_2051.jpg https://wp.optics.arizona.edu/oscoutreach/wp-content/uploads... Or you could cut the four sides separately and just sellotape them together. edit: not much help without measurements sorry - try this: https://www.holeinthewallgang.org/Customer-Content/www/CMS/files/crafts/STEM_info_sheets_for_events_Page_02.jpg https://www.holeinthewallgang.org/Customer-Content/www/CMS/f... The required angles appear to be 54 or 126 degrees: https://data.formsbank.com/pdf_docs_html/304/3049/304991/page_1_thumb_big.png https://data.formsbank.com/pdf_docs_html/304/3049/304991/pag...