bject')
                .attr('x', d.x - currentRadius)
                .attr('y', d.y - currentRadius)
                .attr('width', currentRadius * 2)
                .attr('height', currentRadius * 2)
                .on('mouseover', function(event) {
                // Show tooltip
                d3.select('#tooltip')
                    .style('display', 'block')
                    .html(d.twitterUsername); // Use innerHTML or textContent if plain text
                })
                .on('mousemo