Rulers were used for straight lines, compasses for circles, and protractors for angles. They are often purchased in packs with protractors and compasses. Apart from navigational compasses, other specialty compasses have also been designed to accommodate specific uses. The outcome was an Imperial order for globes, compasses, astrolabe and astronomical rings. Aokigahara has been falsely portrayed as a place where navigational compasses go haywire. Mineral spirits are often used inside liquid-filled compasses and gauges. User-interface elements feature elements like compasses and astrolabes. Such simulators incorporate magnetic and gyro compasses (or repeaters) for steering. Dials were laid out using straight edges and compasses. Lodestones, suspended so they could turn, were the first magnetic compasses. Items to avoid around compasses are magnets of any kind and any electronics. In Tasmania there are many areas with highly magnetized rocks that can greatly influence compasses. Other magnetic compasses have a small sliding counterweight installed on the needle itself. Fluxgate compasses and gradiometers measure the direction and magnitude of magnetic fields. Pieces of magnetite with natural permanent magnetization (lodestones) provided the earliest compasses for navigation.