An interactive poster, comprising: - a first near-field communications, NFC, antenna ; - a first memory configured to store first content; - a controller configured to control operation of a display ; and - a power harvester configured to output power for the controller based on energy received by the first NFC antenna from a user device including an NFC circuit, wherein the first NFC antenna is located at a first position, and wherein the controller is configured to change display of first content to second content when the first NFC antenna is tapped by said user device; a second NFC antenna at a second position, wherein the controller is configured to change display of third content to fourth content when the second NFC antenna is tapped by the user device; a first power detector configured to generate a first detection signal when the first NFC antenna is tapped; a second power detector configured to generate a second detection signal when the second NFC antenna is tapped, wherein the controller is configured to control display of the second content based on the first detection signal and to control display of the fourth content based on the second detection signal; characterized in that the controller is configured to change display of the first content to fifth content when the first NFC antenna and the second NFC antenna are simultaneously tapped by the user device, by controlling display of the fifth content when receiving the first detection signal and the second detection signal simultaneously, wherein the combination of the first detection signal and the second detection signal is mapped to the action of changing display of the first content to the fifth content. - a first near-field communications, NFC, antenna ; - a first memory configured to store first content; - a controller configured to control operation of a display ; and - a power harvester configured to output power for the controller based on energy received by the first NFC antenna from a user device including an NFC circuit, wherein the first NFC antenna is located at a first position, and wherein the controller is configured to change display of first content to second content when the first NFC antenna is tapped by said user device; a second NFC antenna at a second position, wherein the controller is configured to change display of third content to fourth content when the second NFC antenna is tapped by the user device; a first power detector configured to generate a first detection signal when the first NFC antenna is tapped; a second power detector configured to generate a second detection signal when the second NFC antenna is tapped, wherein the controller is configured to control display of the second content based on the first detection signal and to control display of the fourth content based on the second detection signal; characterized in that the controller is configured to change display of the first content to fifth content when the first NFC antenna and the second NFC antenna are simultaneously tapped by the user device, by controlling display of the fifth content when receiving the first detection signal and the second detection signal simultaneously, wherein the combination of the first detection signal and the second detection signal is mapped to the action of changing display of the first content to the fifth content. <EOS>