A woman, viewed from behind, is actively writing or drawing on a large whiteboard in a classroom or lecture hall located in Sofia, Bulgaria

A woman, viewed from behind, is actively writing or drawing on a large whiteboard in a classroom or lecture hall located in Sofia, Bulgaria. She wears a short-sleeved, full-body garment with a repeating circular or floral pattern in shades of green, blue, and brown. Her dark hair is cut short. She holds and operates a large yellow triangular ruler against the lower of two vertically stacked whiteboards. Both whiteboards are extensively covered with handwritten content in black and blue markers. The top board displays a multi-dimensional geometric diagram featuring lines, planes, and angles, along with mathematical notations and Bulgarian text such as "Етажи на S" (Floors of S). The lower board shows coordinate systems, vectors, complex mathematical equations, and additional Bulgarian text, including labels like "Т1, Т2=" and "12ч, S+1". In the foreground, a long, polished wooden lecturer's desk with a light-colored, possibly glass or laminate, top surface spans the width of the frame. On the left side of the desk, a white rectangular enclosure with a circular hole is visible, along with black electrical cables. On the right side of the desk, a smaller orange-and-clear ruler/protractor and several white papers are present. The floor visible beneath the desk is a uniform light brown. The overall environment appears functional and academic.