This bubble chart displays the relationship between engine size, vehicle weight, and fuel efficiency for a range of car models. Each circle's horizontal position represents engine size in liters, its vertical position indicates weight in kilograms, and its size and color encode fuel efficiency in miles per gallon, with a color gradient using `d3.interpolateTurbo`. The visualization uses D3 v7 to render the SVG, with axes scaled by `d3.scaleLinear` and interactive tooltips that appear on mouseover. A legend shows the mapping between bubble radius and efficiency values, while the model names are color-coded along the side.