in src/util.cpp [17:21]
void msg_f(const char *str, int32_t line) { const int8_t line_height = 10; ev3_lcd_fill_rect(0, line * line_height, EV3_LCD_WIDTH, line_height, EV3_LCD_WHITE); ev3_lcd_draw_string(str, 0, line * line_height); }