The triad color scheme is similar to the split-complementary in that it uses three colors.
However, the three colors are spaced equally apart on the color wheel forming a triangle.
If blue is your base color then the two additional colors are the two equal distance from blue on the color wheel.
The pillows on the neutral sofa are tints and shades of the color scheme. It can be very vibrant or more subdued depending on which shades or tints are used.
The use of three colors of equal distance on the color wheel creates a high contrast, vibrant color scheme. It can be intense or calming depending on the use of shades and tints.