select the three upside down triangle wrong, remove the last selection select the three triangle side by side wrong, remove the last selection
page4-192.png page5-134.png page2-140.png
page7-177.png page7-69.png page8-46.png page6-245.png page2-140.png page4-113.png page5-71.png page4-192.png page4-25.png page5-134.png
page4-113.png page7-69.png
select the three building upside down