There are ways to map the WiFi signal in your home or surrounding in 2D but it has some limitations. A YouTuber CNLohr has developed a low-tech way to map and visualize the WiFi strength of a space in 3D. Watch this visualization here.
This system is similar to a WiFi radar, making the use of a battery powered ESP8266 chip to tell a device about signal and measure the strength. So, just by using a simple WiFi module and a CNC mill, he successfully detected the change in a signal in a particular area and thus created a cool visualization. He shows that if you attach an LED to the device, it changes color according to the relative WiFi strength on that area.
Take a look at the clip below to know how to build one for yourself:
